Front and Rear A/C pressure Problem
cris2004
08-16-2010, 11:21 AM
I've just finished replacing the compressor, otube and reciever without solving my problem.
The 1998 Suburban had been sitting a month or so. The AC would cool only to 60-65 on a 100 plus day, normally it will get well into the 40's after a bit.
I had 40 low/200 High front air only, and 55 low/250 high with the rear on. Normal was 28-30L and 290-300H. The lines front and back were, cold/hot as should be, but there was no dripping in the rear, plenty in front.
The pressures equalize smoothly on shut off. I was running a very good aux fan, using water to cool a system that works very well, the condensor in clean on the outside.
What possesed me to swap the parts I don't know, just thought the compressor was getting weak.
The compressor I removed had no oil to drain out. It was a tad bit noisy before BTW, I failed to consider that unfortunately.
The dryer also seemed very light, no oil came out.
The oriface tube was clean, a tiny bit dark, no oil or goo at all.
My new pressures were similar, a bit higher, 40/250 front only and 65/260 with the rear on.
I've had a problem with poor cooling in the past fron too much oil in the system, solved by draining a couple ozs from the rear lines. I tried that next and removed two ozs of oil, not as much as I would have guessed, with it a pound of freon. No oil came form the larger line, only fron the smaller (Liquid?) line.
My new pressures after adding freon to keep the clutch engaged are much lower, 36/155 front and 45/175 when the rear is on.
I've looked up everything I could on the rear air problems and have learned to run both at all times. Also. I've read about the TXV problem. I was reticent to do it but on hindsight I should have thought more. The conflict was, I had a very cold and a hot line in the rear.(but no condensation or cooling), and a clean otube.
Any insight? I suppose the TXV would be my next hacker move, it just doesnt seem to fit completely.
Another question, is it better to fill with gas or liquid?
Any help is greatly appreciated!
Chris
The 1998 Suburban had been sitting a month or so. The AC would cool only to 60-65 on a 100 plus day, normally it will get well into the 40's after a bit.
I had 40 low/200 High front air only, and 55 low/250 high with the rear on. Normal was 28-30L and 290-300H. The lines front and back were, cold/hot as should be, but there was no dripping in the rear, plenty in front.
The pressures equalize smoothly on shut off. I was running a very good aux fan, using water to cool a system that works very well, the condensor in clean on the outside.
What possesed me to swap the parts I don't know, just thought the compressor was getting weak.
The compressor I removed had no oil to drain out. It was a tad bit noisy before BTW, I failed to consider that unfortunately.
The dryer also seemed very light, no oil came out.
The oriface tube was clean, a tiny bit dark, no oil or goo at all.
My new pressures were similar, a bit higher, 40/250 front only and 65/260 with the rear on.
I've had a problem with poor cooling in the past fron too much oil in the system, solved by draining a couple ozs from the rear lines. I tried that next and removed two ozs of oil, not as much as I would have guessed, with it a pound of freon. No oil came form the larger line, only fron the smaller (Liquid?) line.
My new pressures after adding freon to keep the clutch engaged are much lower, 36/155 front and 45/175 when the rear is on.
I've looked up everything I could on the rear air problems and have learned to run both at all times. Also. I've read about the TXV problem. I was reticent to do it but on hindsight I should have thought more. The conflict was, I had a very cold and a hot line in the rear.(but no condensation or cooling), and a clean otube.
Any insight? I suppose the TXV would be my next hacker move, it just doesnt seem to fit completely.
Another question, is it better to fill with gas or liquid?
Any help is greatly appreciated!
Chris
MT-2500
08-17-2010, 08:44 AM
Low on oil is not good.
I would make sure it has the correct charge and the right amount and kind of oil.
System may have to be flushed to get the right amount of oil in it.
Also vacuum out system before charging.
After right charge and amount and kind of oil post back low and high pressure at idle and at 2K rpm.
I would make sure it has the correct charge and the right amount and kind of oil.
System may have to be flushed to get the right amount of oil in it.
Also vacuum out system before charging.
After right charge and amount and kind of oil post back low and high pressure at idle and at 2K rpm.
cris2004
08-17-2010, 10:15 AM
Thanks for the reply.
The system had been working great for several years. It was after sitting a month now that the AC wasn't cooling well.
Years back I did add too much oil, had poor cooling, and corrected it by removing a few ozs after checking my math.
This time, I added 4 pounds of freon, 2 oz oil to the new compressor
and 4 to the drier in spite of there being so little in the old components. I vaac it down for a couple hours to-24hg or whatever and held it shut down for fifteen minutes.
Idle is 45/175, 2000rpm is better today, 32/225! Yesterday there wasn't a significant drop at high RPMs. Now, I may be 2 oz low on oil after yestersdays actions.
My fear was that the oil was pooling again somehow, but that's just a bit a desperation guessing.
It cooled worse after the new stuff, the compressor is quite. There is a big difference in running the front only, and with the rear, but neither was actually working well.
Today, it is better, The car has been sitting but today I'll take it to work and try the AC, it's only the high 90s thank goodness.
If the TXV was stuck open, wouldnt I get liquid to the compressor causing the high 'low' pressure reading? (as I am)
If it's closed, that would seem less disruptive. Could it be passing just enough the make the expansion hose cold but not actually cool the evaporater?
thanks again
The system had been working great for several years. It was after sitting a month now that the AC wasn't cooling well.
Years back I did add too much oil, had poor cooling, and corrected it by removing a few ozs after checking my math.
This time, I added 4 pounds of freon, 2 oz oil to the new compressor
and 4 to the drier in spite of there being so little in the old components. I vaac it down for a couple hours to-24hg or whatever and held it shut down for fifteen minutes.
Idle is 45/175, 2000rpm is better today, 32/225! Yesterday there wasn't a significant drop at high RPMs. Now, I may be 2 oz low on oil after yestersdays actions.
My fear was that the oil was pooling again somehow, but that's just a bit a desperation guessing.
It cooled worse after the new stuff, the compressor is quite. There is a big difference in running the front only, and with the rear, but neither was actually working well.
Today, it is better, The car has been sitting but today I'll take it to work and try the AC, it's only the high 90s thank goodness.
If the TXV was stuck open, wouldnt I get liquid to the compressor causing the high 'low' pressure reading? (as I am)
If it's closed, that would seem less disruptive. Could it be passing just enough the make the expansion hose cold but not actually cool the evaporater?
thanks again
MT-2500
08-17-2010, 10:49 AM
Thanks for the reply.
The system had been working great for several years. It was after sitting a month now that the AC wasn't cooling well.
Years back I did add too much oil, had poor cooling, and corrected it by removing a few ozs after checking my math.
This time, I added 4 pounds of freon, 2 oz oil to the new compressor
and 4 to the drier in spite of there being so little in the old components. I vaac it down for a couple hours to-24hg or whatever and held it shut down for fifteen minutes.
Idle is 45/175, 2000rpm is better today, 32/225! Yesterday there wasn't a significant drop at high RPMs. Now, I may be 2 oz low on oil after yestersdays actions.
My fear was that the oil was pooling again somehow, but that's just a bit a desperation guessing.
It cooled worse after the new stuff, the compressor is quite. There is a big difference in running the front only, and with the rear, but neither was actually working well.
Today, it is better, The car has been sitting but today I'll take it to work and try the AC, it's only the high 90s thank goodness.
If the TXV was stuck open, wouldnt I get liquid to the compressor causing the high 'low' pressure reading? (as I am)
If it's closed, that would seem less disruptive. Could it be passing just enough the make the expansion hose cold but not actually cool the evaporater?
thanks again
Total oil charge should be 11 oz. pag 150.
You are at a hit and miss on oil charge>
Did the replacement compressor have oil in it.
I have got some with a heavy charge10 oz or un know oil.
32/225 at 2K is good pressure and ac should be working good.
Does it hold at 32 low or cycle up and down with compressor and engine running?
The system had been working great for several years. It was after sitting a month now that the AC wasn't cooling well.
Years back I did add too much oil, had poor cooling, and corrected it by removing a few ozs after checking my math.
This time, I added 4 pounds of freon, 2 oz oil to the new compressor
and 4 to the drier in spite of there being so little in the old components. I vaac it down for a couple hours to-24hg or whatever and held it shut down for fifteen minutes.
Idle is 45/175, 2000rpm is better today, 32/225! Yesterday there wasn't a significant drop at high RPMs. Now, I may be 2 oz low on oil after yestersdays actions.
My fear was that the oil was pooling again somehow, but that's just a bit a desperation guessing.
It cooled worse after the new stuff, the compressor is quite. There is a big difference in running the front only, and with the rear, but neither was actually working well.
Today, it is better, The car has been sitting but today I'll take it to work and try the AC, it's only the high 90s thank goodness.
If the TXV was stuck open, wouldnt I get liquid to the compressor causing the high 'low' pressure reading? (as I am)
If it's closed, that would seem less disruptive. Could it be passing just enough the make the expansion hose cold but not actually cool the evaporater?
thanks again
Total oil charge should be 11 oz. pag 150.
You are at a hit and miss on oil charge>
Did the replacement compressor have oil in it.
I have got some with a heavy charge10 oz or un know oil.
32/225 at 2K is good pressure and ac should be working good.
Does it hold at 32 low or cycle up and down with compressor and engine running?
cris2004
08-17-2010, 12:12 PM
Total oil charge should be 11 oz. pag 150.
You are at a hit and miss on oil charge>
Did the replacement compressor have oil in it.
I have got some with a heavy charge10 oz or un know oil.
32/225 at 2K is good pressure and ac should be working good.
Does it hold at 32 low or cycle up and down with compressor and engine running?
I did add pag 150. The replacement (four seasons) did have freeze 32 or something in it, but said to add oil as per manufactures intructions. Since the old one had 0 to drain, I added two oz pag 150 .
I didnt notice it cycling up and down, seemed to hold steady. I didnt wait long, but unhooked everthing and headed 13 miles to work, stop and go in 90 degrees. I don't have the gauges, but the front was close to 50 degrees(when the air speed was lowest), the rear 60 degrees. I would put it in N and run the rpms over two at the few lights I hit. I was hoping it would get better on the drive, but it did not.
Before the problem, it would cool high 30s low 40s at low air speed, even when hot outside.
The compressor remains quiet.
At this point, its a we bit better than before changing parts, but still well under the usual performance of 28/320 and 40 degrees at the vents.
I do appreciate the insight
You are at a hit and miss on oil charge>
Did the replacement compressor have oil in it.
I have got some with a heavy charge10 oz or un know oil.
32/225 at 2K is good pressure and ac should be working good.
Does it hold at 32 low or cycle up and down with compressor and engine running?
I did add pag 150. The replacement (four seasons) did have freeze 32 or something in it, but said to add oil as per manufactures intructions. Since the old one had 0 to drain, I added two oz pag 150 .
I didnt notice it cycling up and down, seemed to hold steady. I didnt wait long, but unhooked everthing and headed 13 miles to work, stop and go in 90 degrees. I don't have the gauges, but the front was close to 50 degrees(when the air speed was lowest), the rear 60 degrees. I would put it in N and run the rpms over two at the few lights I hit. I was hoping it would get better on the drive, but it did not.
Before the problem, it would cool high 30s low 40s at low air speed, even when hot outside.
The compressor remains quiet.
At this point, its a we bit better than before changing parts, but still well under the usual performance of 28/320 and 40 degrees at the vents.
I do appreciate the insight
MT-2500
08-17-2010, 01:07 PM
I did add pag 150. The replacement (four seasons) did have freeze 32 or something in it, but said to add oil as per manufactures intructions. Since the old one had 0 to drain, I added two oz pag 150 .
I didnt notice it cycling up and down, seemed to hold steady. I didnt wait long, but unhooked everthing and headed 13 miles to work, stop and go in 90 degrees. I don't have the gauges, but the front was close to 50 degrees(when the air speed was lowest), the rear 60 degrees. I would put it in N and run the rpms over two at the few lights I hit. I was hoping it would get better on the drive, but it did not.
Before the problem, it would cool high 30s low 40s at low air speed, even when hot outside.
The compressor remains quiet.
At this point, its a we bit better than before changing parts, but still well under the usual performance of 28/320 and 40 degrees at the vents.
I do appreciate the insight
Four seasons is not good.
Where and what was the freeze 32 put in?
I didnt notice it cycling up and down, seemed to hold steady. I didnt wait long, but unhooked everthing and headed 13 miles to work, stop and go in 90 degrees. I don't have the gauges, but the front was close to 50 degrees(when the air speed was lowest), the rear 60 degrees. I would put it in N and run the rpms over two at the few lights I hit. I was hoping it would get better on the drive, but it did not.
Before the problem, it would cool high 30s low 40s at low air speed, even when hot outside.
The compressor remains quiet.
At this point, its a we bit better than before changing parts, but still well under the usual performance of 28/320 and 40 degrees at the vents.
I do appreciate the insight
Four seasons is not good.
Where and what was the freeze 32 put in?
cris2004
08-17-2010, 01:54 PM
I regret not waiting for the delco/dephi again, but I did have the problem before switching.
The freeze 32 was in the compressor, had a bright label and all that. I didnt really look at it too close, I though f32 was goofy freon gas additive.
The freeze 32 was in the compressor, had a bright label and all that. I didnt really look at it too close, I though f32 was goofy freon gas additive.
MT-2500
08-17-2010, 02:04 PM
I regret not waiting for the delco/dephi again, but I did have the problem before switching.
The freeze 32 was in the compressor, had a bright label and all that. I didnt really look at it too close, I though f32 was goofy freon gas additive.
FREEZE 32 IS A BLEND THAT MAY HAVE BUTANE/PROPANE IN IT.
A GOOD SPARK OR FLAME MAKES A GOOD BOMB.
If it is not pumping good pressure pitch the 4 season and get a good compressor.
New not rebuilt is the way to go on compressors.
The freeze 32 was in the compressor, had a bright label and all that. I didnt really look at it too close, I though f32 was goofy freon gas additive.
FREEZE 32 IS A BLEND THAT MAY HAVE BUTANE/PROPANE IN IT.
A GOOD SPARK OR FLAME MAKES A GOOD BOMB.
If it is not pumping good pressure pitch the 4 season and get a good compressor.
New not rebuilt is the way to go on compressors.
cris2004
08-17-2010, 02:10 PM
It was new, I'd gladly detonate the sucker if that helps!
MT-2500
08-17-2010, 03:03 PM
It was new, I'd gladly detonate the sucker if that helps!
New is better.
Should be under warranty if bad.
If compressor is pumping good you should see some compressor clutch cycling as pressure drops under 28 low side.
New is better.
Should be under warranty if bad.
If compressor is pumping good you should see some compressor clutch cycling as pressure drops under 28 low side.
mishalah
08-17-2010, 03:21 PM
OK...hold on here. The carbon/propane based refrigerants are no more flammable than any of the environmentally UNSAFE freons on the market. That's hype by the oldtimers and freon sellers. I've been using the alternatives for over 25 years in over a dozen different vehicles. I've read all the industry standard sheets and was involved in legislation protecting the consumer's rights to use the alternatives for many years. They are lighter, more effiicient, create less pressure in the compressor, and have no negative environmental effects. There has NEVER been a documented incident of fire or explosion due to alternative refrigerants.
That said, I wouldn't start a system with a mix of Freeze 12 and R-134a. Even though they are mixable aith no negative consequences, it's better to go with one or the other. Since Freeze 12 is just the gas, and not the oil charge itself, I don't know why a new compressor would have it labeled as being in it. Even if Freeze 12 was used prior to rebuilding or replacing the compressor it wouldn't affect the compressor since the alternative refrigerants can all be used with any of the oils. I use Enviro-Safe myself, and have for at least 10 years with great cooling and no problems whatsoever.
But you're problem seems more like circulation of the refrigerant. First, your -24hg of vacuum when you evacuated th esystem was not enough. It needs to hold at -30 for at least 30 minutes (2 hours is a better test) with the pump OFF. If it doesn't get to -30 there is a leak or partial blockage somewhere. After you get it to hold at -30 you can add your refrigerant and cycle it back into the system. And, yes, 30+- at 2000-2500 rpms is good. You should have plenty of cold air at the vents. However, if your ambient temp is 100+ you will not get 40 degree vent air. 60 would actually be pretty good. I think the rule of thumb used to be ambient minus 30-40 at best. If your burb is a dark color like mine it takes twice as long to cool down.
Your compressor oil is a different problem, too. I know you don't want to start over, but you need to know exactly how much oil you have in there. If you got no oil out of the drier that's not a good sign. Obviously, you need to ad back the recommended amount. Most rebuilt comps have some oil in them. You can dump it and see how much comes out until it's empty. I think you have to turn the vanes to make sure you get it all, but turning them backward can damage the compressor. If you start from "0" it's a lot easier than guessing. Apparently, our compressors have a history of losing their oil and rattling themselves to death....and too much oil makes the system work like crap.
If your compressor has a warranty you might want to take it back and get another one. I know it's a PITA, but what you have now isn't doing the job...and you don't really know what is in your system. I've replaced compressors and had the "new" one self-destruct almost immediately (using R-134 or R12 or any other). Remember where they are rebuilt. Make sure your valves on top are not leaking --- another common problem.
That said, I wouldn't start a system with a mix of Freeze 12 and R-134a. Even though they are mixable aith no negative consequences, it's better to go with one or the other. Since Freeze 12 is just the gas, and not the oil charge itself, I don't know why a new compressor would have it labeled as being in it. Even if Freeze 12 was used prior to rebuilding or replacing the compressor it wouldn't affect the compressor since the alternative refrigerants can all be used with any of the oils. I use Enviro-Safe myself, and have for at least 10 years with great cooling and no problems whatsoever.
But you're problem seems more like circulation of the refrigerant. First, your -24hg of vacuum when you evacuated th esystem was not enough. It needs to hold at -30 for at least 30 minutes (2 hours is a better test) with the pump OFF. If it doesn't get to -30 there is a leak or partial blockage somewhere. After you get it to hold at -30 you can add your refrigerant and cycle it back into the system. And, yes, 30+- at 2000-2500 rpms is good. You should have plenty of cold air at the vents. However, if your ambient temp is 100+ you will not get 40 degree vent air. 60 would actually be pretty good. I think the rule of thumb used to be ambient minus 30-40 at best. If your burb is a dark color like mine it takes twice as long to cool down.
Your compressor oil is a different problem, too. I know you don't want to start over, but you need to know exactly how much oil you have in there. If you got no oil out of the drier that's not a good sign. Obviously, you need to ad back the recommended amount. Most rebuilt comps have some oil in them. You can dump it and see how much comes out until it's empty. I think you have to turn the vanes to make sure you get it all, but turning them backward can damage the compressor. If you start from "0" it's a lot easier than guessing. Apparently, our compressors have a history of losing their oil and rattling themselves to death....and too much oil makes the system work like crap.
If your compressor has a warranty you might want to take it back and get another one. I know it's a PITA, but what you have now isn't doing the job...and you don't really know what is in your system. I've replaced compressors and had the "new" one self-destruct almost immediately (using R-134 or R12 or any other). Remember where they are rebuilt. Make sure your valves on top are not leaking --- another common problem.
MT-2500
08-17-2010, 04:33 PM
OK...hold on here. The carbon/propane based refrigerants are no more flammable than any of the environmentally UNSAFE freons on the market. That's hype by the oldtimers and freon sellers. I've been using the alternatives for over 25 years in over a dozen different vehicles. I've read all the industry standard sheets and was involved in legislation protecting the consumer's rights to use the alternatives for many years. They are lighter, more effiicient, create less pressure in the compressor, and have no negative environmental effects. There has NEVER been a documented incident of fire or explosion due to alternative refrigerants.
That said, I wouldn't start a system with a mix of Freeze 12 and R-134a. Even though they are mixable aith no negative consequences, it's better to go with one or the other. Since Freeze 12 is just the gas, and not the oil charge itself, I don't know why a new compressor would have it labeled as being in it. Even if Freeze 12 was used prior to rebuilding or replacing the compressor it wouldn't affect the compressor since the alternative refrigerants can all be used with any of the oils. I use Enviro-Safe myself, and have for at least 10 years with great cooling and no problems whatsoever.
But you're problem seems more like circulation of the refrigerant. First, your -24hg of vacuum when you evacuated th esystem was not enough. It needs to hold at -30 for at least 30 minutes (2 hours is a better test) with the pump OFF. If it doesn't get to -30 there is a leak or partial blockage somewhere. After you get it to hold at -30 you can add your refrigerant and cycle it back into the system. And, yes, 30+- at 2000-2500 rpms is good. You should have plenty of cold air at the vents. However, if your ambient temp is 100+ you will not get 40 degree vent air. 60 would actually be pretty good. I think the rule of thumb used to be ambient minus 30-40 at best. If your burb is a dark color like mine it takes twice as long to cool down.
Your compressor oil is a different problem, too. I know you don't want to start over, but you need to know exactly how much oil you have in there. If you got no oil out of the drier that's not a good sign. Obviously, you need to ad back the recommended amount. Most rebuilt comps have some oil in them. You can dump it and see how much comes out until it's empty. I think you have to turn the vanes to make sure you get it all, but turning them backward can damage the compressor. If you start from "0" it's a lot easier than guessing. Apparently, our compressors have a history of losing their oil and rattling themselves to death....and too much oil makes the system work like crap.
If your compressor has a warranty you might want to take it back and get another one. I know it's a PITA, but what you have now isn't doing the job...and you don't really know what is in your system. I've replaced compressors and had the "new" one self-destruct almost immediately (using R-134 or R12 or any other). Remember where they are rebuilt. Make sure your valves on top are not leaking --- another common problem.
Good info on the AC recharging and oil.
But on blends with propane/butane mixers.
There have be more than several cases of it blowing up and sitting cars on fire.
You might try telling that to the person that tried demonstrating that they would not blow things up.
He thought the same thing.
He got burnt bad and blowed up the car to.
I tested that crap outside by opening up a can in the air and hitting the gas with a torch.
Dam stuff about blowed my socks off.
No way am I going to use it or put it in any ones car.
That said, I wouldn't start a system with a mix of Freeze 12 and R-134a. Even though they are mixable aith no negative consequences, it's better to go with one or the other. Since Freeze 12 is just the gas, and not the oil charge itself, I don't know why a new compressor would have it labeled as being in it. Even if Freeze 12 was used prior to rebuilding or replacing the compressor it wouldn't affect the compressor since the alternative refrigerants can all be used with any of the oils. I use Enviro-Safe myself, and have for at least 10 years with great cooling and no problems whatsoever.
But you're problem seems more like circulation of the refrigerant. First, your -24hg of vacuum when you evacuated th esystem was not enough. It needs to hold at -30 for at least 30 minutes (2 hours is a better test) with the pump OFF. If it doesn't get to -30 there is a leak or partial blockage somewhere. After you get it to hold at -30 you can add your refrigerant and cycle it back into the system. And, yes, 30+- at 2000-2500 rpms is good. You should have plenty of cold air at the vents. However, if your ambient temp is 100+ you will not get 40 degree vent air. 60 would actually be pretty good. I think the rule of thumb used to be ambient minus 30-40 at best. If your burb is a dark color like mine it takes twice as long to cool down.
Your compressor oil is a different problem, too. I know you don't want to start over, but you need to know exactly how much oil you have in there. If you got no oil out of the drier that's not a good sign. Obviously, you need to ad back the recommended amount. Most rebuilt comps have some oil in them. You can dump it and see how much comes out until it's empty. I think you have to turn the vanes to make sure you get it all, but turning them backward can damage the compressor. If you start from "0" it's a lot easier than guessing. Apparently, our compressors have a history of losing their oil and rattling themselves to death....and too much oil makes the system work like crap.
If your compressor has a warranty you might want to take it back and get another one. I know it's a PITA, but what you have now isn't doing the job...and you don't really know what is in your system. I've replaced compressors and had the "new" one self-destruct almost immediately (using R-134 or R12 or any other). Remember where they are rebuilt. Make sure your valves on top are not leaking --- another common problem.
Good info on the AC recharging and oil.
But on blends with propane/butane mixers.
There have be more than several cases of it blowing up and sitting cars on fire.
You might try telling that to the person that tried demonstrating that they would not blow things up.
He thought the same thing.
He got burnt bad and blowed up the car to.
I tested that crap outside by opening up a can in the air and hitting the gas with a torch.
Dam stuff about blowed my socks off.
No way am I going to use it or put it in any ones car.
MT-2500
08-18-2010, 10:17 AM
MT-2500
08-18-2010, 10:21 AM
Detailed Questions About HC-12a ®, OZ-12 ®, DURACOOL 12a ®, EC-12a, and other Flammable Hydrocarbon Refrigerants
If you have questions beyond those in this fact sheet, or would like paper copies of the lists, please call the Stratospheric Ozone Protection Hotline toll-free at 1 (800) 296-1996 or direct dial (202) 343-9210 to leave inquiries.
1. What are HC-12a® and OZ-12®?
2. What is DURACOOL 12a®? Is there a difference between HC-12a® and DURACOOL 12a®?
3. What is the legal status of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®?
4. What is EC-12a and what is its legal status?
5. May hydrocarbon refrigerants be used to replace CFC-12, commonly referred to as "Freon®," in cars?
6. How did EPA make this determination?
7. Why is it legal to use hydrocarbon refrigerants as CFC-12 substitutes in industrial process refrigeration, but not elsewhere?
8. Gasoline and brake fluid are flammable, but they're allowed in cars. Why not hydrocarbon refrigerants?
9. Is the sale of hydrocarbon refrigerants legal?
10. Since the autoignition temperature of HFC-134a is lower than that of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®, doesn't that mean that HFC-134a is more flammable than these hydrocarbons?
11. What is a "sham retrofit" of a motor vehicle A/C system?
12. May hydrocarbon refrigerants be vented?
13. What other regulations restrict the use and handling of hydrocarbon refrigerants?
14. Are there other refrigerants that can replace CFC-12?
15. Are there any advantages to using flammable hydrocarbon refrigerants?
16. Has EPA found any flammable refrigerants acceptable under SNAP?
17. Is it legal to replace HFC-134a in a motor vehicle with hydrocarbon refrigerants such as DURACOOL 12a® and HC-12a®?
* What are HC-12a® and OZ-12®?
HC-12a® and OZ-12® brand hydrocarbon refrigerant blends are flammable refrigerants. Their primary components are hydrocarbons, which are flammable substances such as propane and butane. HC-12a® and OZ-12® are registered trademarks of OZ Technology, Inc. HC-12a® has been marketed since 1994. OZ-12® was a similar blend marketed until the introduction of HC-12a® . Both products have been reviewed by EPA under the Significant New Alternatives Policy (SNAP) program. More information about the SNAP program is available from the hotline listed at the top of this page.
Note that EPA refers to the chemical composition of HC-12a® as Hydrocarbon Blend B. EPA considers any substance with that chemical composition, no matter what its trade name is, to be Hydrocarbon Blend B and to have the same legal status that HC-12a® has.
In order to meet Department of Transportation requirements for shipping HC-12a® in six-ounce cans (DOT refers to these cans as DOT 2Q containers), OZ Technology reduced the vapor pressure of HC-12a® in June, 1998. In order to reduce the vapor pressure, OZ Technology changed the composition of HC-12a®. EPA does not consider this reformulated HC-12a® to be the same as Hydrocarbon Blend B. The reformulated HC-12a® has not been submitted for SNAP review, and thus cannot be marketed or used as a substitute for ozone-depleting substances.
* What is DURACOOL 12a®? Is there a difference between HC-12a® and DURACOOL 12a®?
DURACOOL 12a® has the same chemical composition as the HC-12a® formulation that was submitted for SNAP review as Hydrocarbon Blend B. Both HC-12a® and DURACOOL 12a® are different than the new formulation of HC-12a® in six-ounce cans. DURACOOL 12a® is the registered trademark of Duracool Limited, the Canadian company that has manufactured DURACOOL 12a® since 1997. Duracool Limited and OZ Technology, the manufacturer of HC-12a®, are separate, unrelated companies with their own manufacturing facilities and distribution mechanisms.
* What is the legal status of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®?
It has been illegal since July 13, 1995 to replace CFC-12 with the HC-12a® formulation that was submitted for SNAP review in any refrigeration or A/C application other than industrial process refrigeration. The same prohibition for OZ-12® took effect on April 18, 1994. Because DURACOOL 12a® has the same chemical composition as the HC-12a® formulation that was submitted for SNAP review (i.e., Hydrocarbon Blend B), DURACOOL 12a® is also subject to the same restrictions.
HC-12a®, as reformulated to meet DOT requirements, is not the same as Hydrocarbon Blend B and has not been submitted for SNAP review. OZ Technology is therefore prohibited from marketing this blend as a substitute for any ozone-depleting substance. In addition, any use of this blend as a substitute for CFC-12 or any other ozone-depleting chemical, in industrial process refrigeration or any other refrigeration or A/C end use, is prohibited under the Clean Air Act.
Since HC-12a® as submitted for SNAP review, is chemically different from HC-12a®, as reformulated to meet DOT requirements, and since it has a different legal status under the Clean Air Act, users of any substance marketed as HC-12a® should be aware of which HC-12a® they have purchased.
Note that the Clean Air Act does not regulate the use of any of these hydrocarbon refrigerants when they are used as replacements for non-ozone-depleting chemicals such as HFC-134a. However, many states prohibit using flammable refrigerants in motor vehicles, regardless of which original refrigerant was used in the vehicle.
* What is EC-12a and what is its legal status?
Because it has not been submitted for review under the SNAP program, EPA is not aware of EC-12a's chemical composition. EC-12a is not legal to sell or use in any refrigeration or A/C end-use as a substitute for CFC-12 or any other ozone-depleting refrigerant, because it has not been submitted for SNAP review.
* May hydrocarbon refrigerants be used to replace CFC-12, commonly referred to as "Freon® ," in cars?
No. It is illegal to use hydrocarbon refrigerants like HC-12a® and DURACOOL 12a® as substitutes for CFC-12 in automobile or truck air conditioning under any circumstances.
* How did EPA make this determination?
The Clean Air Act, as amended in 1990, required EPA to establish a program to review substitutes for ozone-depleting substances, including refrigerants. EPA's Significant New Alternatives Policy (SNAP) program carries out this mandate. Manufacturers of substitutes must submit information to EPA about the products, including ozone depletion potential, global warming potential, and toxicity and flammability data. EPA then compares these characteristics to both the refrigerant being replaced and the other available substitutes.
Most refrigerants submitted to EPA for review under SNAP have been found acceptable, often subject to certain conditions. A full list of alternatives is available online. In particular, several refrigerants have been listed acceptable for use as CFC-12 substitutes in motor vehicle air conditioning, subject to certain conditions on their use. Each acceptable alternative refrigerant has been demonstrated to a) be safer for human health and the environment than the original refrigerant, and b) pose a level of risk similar to that of other acceptable alternatives.
Flammable refrigerants pose a special challenge, because air conditioning and refrigeration systems in the US have been designed to use nonflammable refrigerants. They are not designed to protect users, service technicians, and disposal personnel from the possibility of fire. Therefore, the use of flammable refrigerants in existing systems may pose a risk not found with nonflammable fluids.
Although new systems may be designed to provide that protection, they are not specifically designed so today. Demonstrating that a flammable refrigerant can be used safely in current systems, whether existing or new, requires a comprehensive, detailed, scientifically valid risk assessment. EPA has required a risk assessment for flammable refrigerants since the inception of the SNAP program in 1994. An assessment must address potential leak scenarios such as collisions, servicing errors, and disposal procedures. In addition, it must consider ignition sources ranging from cigarette lighters or matches to sparks caused during a collision.
OZ Technology has submitted reports that it states demonstrate the safety of using OZ-12® and HC-12a® in systems not designed to use such flammable refrigerants. However, after careful review of each document, EPA determined that none of the reports represented valid a risk assessment. Until such assessments are performed, EPA believes that flammable refrigerants like HC-12a®, OZ-12® and DURACOOL 12a® may pose potential risks not present when using nonflammable refrigerants. For these reasons, EPA does not allow the use of HC-12a®, OZ-12® or DURACOOL 12a® as substitutes for CFC-12 outside of industrial process refrigeration. (Note that HC-12a®, as reformulated to meet DOT requirements, is not permitted to be sold or used as a substitute for ozone-depleting chemicals in industrial process refrigeration, since it has not been submitted to SNAP for review.)
* Why is it legal to use hydrocarbon refrigerants as CFC-12 substitutes in industrial process refrigeration, but not elsewhere?
EPA has not yet received data that adequately address the safety issues of hydrocarbon refrigerants in applications other than industrial process refrigeration. Flammability risks depend on the type of refrigeration or air-conditioning system. Industrial process refrigeration, for instance, does not include air conditioning, which pipes refrigerated air directly into occupied areas. Industrial process refrigeration generally refers to complex customized appliances used in the chemical, pharmaceutical, petrochemical and manufacturing industries. Direct risk to human health is reduced in industrial process refrigeration; for example, access to areas near the system is typically restricted. In addition, other regulations exist to protect the safety of industrial workers.
EPA will review any additional material that is submitted under SNAP regarding the safety considerations of using hydrocarbon refrigerants in systems other than industrial process refrigeration.
* Gasoline and brake fluid are flammable, but they're allowed in cars. Why not hydrocarbon refrigerants?
Because EPA has been directed by Congress, under the SNAP program, to consider the safety aspects of alternative refrigerants for CFC-12 (as well as their environmental characteristics), it is necessary to address the safety aspects of using a flammable refrigerant in motor vehicle A/C systems originally designed for CFC-12, before that refrigerant can be approved.
There are good reasons why gasoline and other fluids may be used safely while the use of hydrocarbon refrigerants in A/C systems may not be safe. Gasoline and other flammable substances are used in systems designed specifically for flammable fluids. A gas tank is deliberately placed in the middle of the rear part of a vehicle to protect it against collisions. Air conditioner condensers, in contrast, are placed at the very front of the car to maintain good air flow. Unfortunately, this location means that condensers may be punctured during a front-end collision. Another difference is that unlike gasoline lines, air conditioners include lines that provide cooling directly to occupied areas -- in this case, passenger compartments. Flammability risk is extremely dependent on the specific system being considered; the simple presence of other flammable fluids in a car does not address the safety of using hydrocarbon refrigerants in an automobile air conditioner.
* Is sale of hydrocarbon refrigerants legal?
Sale of subtitute refrigerants listed under the SNAP program is not regulated under SNAP. However, statutes and regulations issued by other federal, state, or local agencies may control the sale of these products, including illegal advertising.
* Since the autoignition temperature of HFC-134a is lower than that of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®, doesn't that mean that HFC-134a is more flammable than these hydrocarbons?
According to both Underwriters Laboratories and the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE), the main standard-setting body for refrigerants in the U.S., hydrocarbons are flammable materials. Flammability, as defined by the American Society for Testing Materials (ASTM) E-681 standard test procedure for refrigerants, means that a substance will ignite at atmospheric pressure when mixed in some concentration in air at normal temperature and pressure. The minimum and maximum concentrations at which ignition will occur are called the lower and upper flammability limits in air. Hydrocarbons, like the components of HC-12a® and DURACOOL 12a®, become flammable at concentrations as low as 2% by volume. These values are well-established in published literature.
Autoignition temperature is a distinct measure from flammability limits in air. Specifically, this test measures the temperature at which a substance will spontaneously ignite, without any external ignition source like a match or lighter.
Certain documents claim that because the autoignition temperature of HFC-134a is below 750 degrees Celsius (1382 degrees Fahrenheit), it is flammable, and because the autoignition temperature of hydrocarbon refrigerant blends such as HC-12a® is above 750 degrees Celsius, it is nonflammable. However, this statement misrepresents the procedure used by Underwriters Laboratories to classify refrigerants.
UL first examines whether a refrigerant burns in air at some concentration and normal pressure and temperature. If it does ignite under these conditions, it is classified as flammable. Hydrocarbons, like the components of HC-12a® and DURACOOL 12a®, are classified as flammable. (Note that hydrocarbon refrigerant manufacturers recognize that their products are flammable, and label containers for those products with the word "flammable.")
If a refrigerant is not classified as flammable as a result of this test procedure, UL then uses the autoignition temperature to distinguish between practically nonflammable refrigerants (meaning the autoignition temperature is below 750 degrees Celsius) and nonflammable refrigerants (meaning the autoignition temperature is above 750 degrees Celsius). HFC-134a does not ignite, regardless of concentration, at atmospheric temperatures and pressures. This means that at atmospheric pressures and temperatures, if a can of HFC-134a is opened and a lit match is placed in front of the can, the HFC-134a will extinguish the match. HFC-134a is classified by UL as practically nonflammable because its autoignition temperature is below 750 Celsius. Note that UL lists most alternative refrigerants as practically nonflammable. HCFC-22, the refrigerant used in most home air-conditioning, is also classified as practically non-flammable.
* What is a "sham retrofit" of a motor vehicle A/C system?
EPA does not regulate the use of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a® as substitutes for HFC-134a in motor vehicles. Certain materials have circulated claiming that by first converting a system from CFC-12 to HFC-134a, the system may then be converted to use a hydrocarbon refrigerant without violating the original prohibition against using hydrocarbons as substitutes for CFC-12. Thus, the question arises about the definition of a legitimate retrofit. This definition hinges on two distinct principles: complying with the conditions placed on using HFC-134a under the SNAP program, and the intent of the retrofit.
In accordance with the SNAP rules, a retrofit from CFC-12 to HFC-134a must meet certain requirements. The CFC-12 must be completely recovered in accordance with regulations issued under section 609 of the Clean Air Act. Fittings designed for use with HFC-134a must be permanently attached to the system. These fittings mechanically prevent the mixing of HFC-134a with CFC-12 and other refrigerants. Finally, the system must be labeled, and the label must contain detailed information as described by the SNAP rule. Some vehicles also require the installation of a compressor shutoff switch. Performing these activities complies with the letter of the SNAP regulations.
Even such compliance may not, however, indicate a legitimate retrofit. For example, HFC-134a should be used with a different lubricating oil from CFC-12; if the lubricant is not changed, the air conditioner will not work. Similarly, a vehicle must be charged with the correct amount of HFC-134a in order for the air conditioner to work. Failure to take these steps indicates that the technician does not truly intend to convert the vehicle's air conditioner to work with HFC-134a, and the subsequent installation of a hydrocarbon refrigerant such as HC-12a® or DURACOOL 12a® may violate the prohibition against using hydrocarbon refrigerants as CFC-12 substitutes.
Other indications of a sham retrofit also exist, including the timing of the retrofit. In general, if a car arrives in a repair shop containing CFC-12 and leaves containing a hydrocarbon refrigerant, it is likely that it underwent a sham retrofit, regardless of what actually occurred in the shop. Generally, if HFC-134a is charged into a system and then immediately removed, such a temporary retrofit to HFC-134a was likely intended solely to allow the use of HC-12a®, DURACOOL 12a®, or other hydrocarbon refrigerant in a car designed to use CFC-12. EPA is currently investigating several complaints, and believes indications such as those described above support finding a Clean Air Act violation.
* May hydrocarbon refrigerants be vented?
No. The Clean Air Act prohibits the venting of any refrigerant during the service, maintenance, repair, or disposal of air conditioning and refrigeration systems. When working on a system containing a hydrocarbon refrigerant such as HC-12a® or DURACOOL 12a®, the technician must recover the refrigerant into a suitable container and safely dispose of it.
* What other regulations restrict the use and handling of hydrocarbon refrigerants?
In addition to the prohibition on use described above, and the federal law banning the venting of all refrigerants, there are also state and local statutes and regulations that relate to certain uses of hydrocarbons. As of the printing date of this fact sheet, EPA is aware that the following states prohibit the use of flammable refrigerants in automobile air conditioners: Arkansas, Arizona, Connecticut, Florida, Idaho, Indiana, Iowa, Kansas, Louisiana, Maryland, Nebraska, North Dakota, Oklahoma, Texas, Utah, Virginia, Washington, Wisconsin, and the District of Columbia.
Local fire codes also often restrict the storage of flammable materials. In addition, other federal, state, and local regulatory agencies may have regulations related to flammable refrigerants. Check with these authorities for more information.
* Are there other refrigerants that can replace CFC-12?
Yes. Lists of alternatives in other sectors are available online and from our hotline at 800-296-1996. In addition, the fact sheet titled "Choosing and Using Alternative Refrigerants for Motor Vehicle Air Conditioning" lists all SNAP-reviewed motor vehicle refrigerants and conditions on the use of those listed as acceptable.
* Are there any advantages to using flammable hydrocarbon refrigerants?
Many flammable refrigerants offer potential energy efficiency savings, lower global warming potentials, low toxicity, and low cost. EPA believes that, with responsible development, flammable refrigerants have a role to play in the transition away from ozone-depleting substances. However, such development must adequately address safety concerns associated with manufacturing, use, servicing, and disposal of these new products. EPA is aware of several successful uses of flammable refrigerants, and welcomes future development of systems designed to be used with them.
The primary drawback to the use of flammable refrigerants today is that most existing systems are not designed to protect people from that flammability. In order to find a flammable refrigerant acceptable, EPA requires the completion of a risk assessment to determine the additional hazard posed by that flammability and necessary steps to mitigate any additional hazard. EPA believes hydrocarbons and other flammable refrigerants offer the potential to be good substitutes for ozone-depleting refrigerants. The best possibilities exist in the design of new equipment that includes safety features to protect against a fire or explosion. Several such systems are now being sold and developed around the world. EPA has always encouraged U.S. businesses to consider using hydrocarbon refrigerants in such newly designed systems.
* Has EPA found any flammable refrigerants acceptable under SNAP?
EPA found the flammable refrigerant HFC-152a acceptable for use in new household refrigerators and freezers. This determination was based on a detailed assessment of the risks posed by this flammable refrigerant in this particular application. Note that HFC-152a, which is a single chemical rather than a blend, is not a hydrocarbon. The fact that HFC-152a was found acceptable in refrigerators cannot be read as encompassing all hydrocarbon or other flammable refrigerants in all end-uses. A risk assessment relates only to the specific end-use and refrigerant.
* Is it legal to replace HFC-134a in a motor vehicle with hydrocarbon refrigerants such as DURACOOL 12a® and HC-12a®?
In certain circumstances, the replacement of HFC-134a in a motor vehicle with hydrocarbon refrigerants might be permitted. At a minimum, in order to avoid violating the Clean Air Act, the motor vehicle A/C system must have either been originally designed for use with HFC-134a refrigerant, or must have been previously retrofitted from CFC-12 to HFC-134a refrigerant, AND no sham retrofit must have occurred to convert the system to the hydrocarbon refrigerant. In order to avoid violating other laws, the replacement of the refrigerant must not violate any state or local prohibition on the use of flammable refrigerants in motor vehicle A/C systems.
The following 19 states ban the use of flammable refrigerants such as HC-12a® and DURACOOL 12a® in motor vehicle air conditioning, regardless of the original refrigerant: Arkansas, Arizona, Connecticut, Florida, Idaho, Indiana, Iowa, Kansas, Louisiana, Maryland, Nebraska, North Dakota, Oklahoma, Texas, Utah, Virginia, Wisconsin, Washington, and the District of Columbia.
EPA and hotline staff will not, based solely on facts given in a phone call or letter, determine the legality under the SNAP program of using a hydrocarbon refrigerant in a motor vehicle retrofitted to use HFC-134a, because the determination depends on many factors, including the nature of the retrofit from CFC-12 to HFC-134a, the reason for the retrofit, and the exact procedure and timing involved.
If you plan to change a car from HFC-134a to a hydrocarbon refrigerant such as HC-12a® and DURACOOL 12a®, you should consider that auto manufacturers have stated that changing the refrigerant in new vehicles designed for use with HFC-134a will void the warranty and may damage the system. If the air conditioner on a new car or truck is not working, consult a qualified mechanic or your dealer.
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Print As-Is
Last updated on Wednesday, March 03, 2010
If you have questions beyond those in this fact sheet, or would like paper copies of the lists, please call the Stratospheric Ozone Protection Hotline toll-free at 1 (800) 296-1996 or direct dial (202) 343-9210 to leave inquiries.
1. What are HC-12a® and OZ-12®?
2. What is DURACOOL 12a®? Is there a difference between HC-12a® and DURACOOL 12a®?
3. What is the legal status of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®?
4. What is EC-12a and what is its legal status?
5. May hydrocarbon refrigerants be used to replace CFC-12, commonly referred to as "Freon®," in cars?
6. How did EPA make this determination?
7. Why is it legal to use hydrocarbon refrigerants as CFC-12 substitutes in industrial process refrigeration, but not elsewhere?
8. Gasoline and brake fluid are flammable, but they're allowed in cars. Why not hydrocarbon refrigerants?
9. Is the sale of hydrocarbon refrigerants legal?
10. Since the autoignition temperature of HFC-134a is lower than that of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®, doesn't that mean that HFC-134a is more flammable than these hydrocarbons?
11. What is a "sham retrofit" of a motor vehicle A/C system?
12. May hydrocarbon refrigerants be vented?
13. What other regulations restrict the use and handling of hydrocarbon refrigerants?
14. Are there other refrigerants that can replace CFC-12?
15. Are there any advantages to using flammable hydrocarbon refrigerants?
16. Has EPA found any flammable refrigerants acceptable under SNAP?
17. Is it legal to replace HFC-134a in a motor vehicle with hydrocarbon refrigerants such as DURACOOL 12a® and HC-12a®?
* What are HC-12a® and OZ-12®?
HC-12a® and OZ-12® brand hydrocarbon refrigerant blends are flammable refrigerants. Their primary components are hydrocarbons, which are flammable substances such as propane and butane. HC-12a® and OZ-12® are registered trademarks of OZ Technology, Inc. HC-12a® has been marketed since 1994. OZ-12® was a similar blend marketed until the introduction of HC-12a® . Both products have been reviewed by EPA under the Significant New Alternatives Policy (SNAP) program. More information about the SNAP program is available from the hotline listed at the top of this page.
Note that EPA refers to the chemical composition of HC-12a® as Hydrocarbon Blend B. EPA considers any substance with that chemical composition, no matter what its trade name is, to be Hydrocarbon Blend B and to have the same legal status that HC-12a® has.
In order to meet Department of Transportation requirements for shipping HC-12a® in six-ounce cans (DOT refers to these cans as DOT 2Q containers), OZ Technology reduced the vapor pressure of HC-12a® in June, 1998. In order to reduce the vapor pressure, OZ Technology changed the composition of HC-12a®. EPA does not consider this reformulated HC-12a® to be the same as Hydrocarbon Blend B. The reformulated HC-12a® has not been submitted for SNAP review, and thus cannot be marketed or used as a substitute for ozone-depleting substances.
* What is DURACOOL 12a®? Is there a difference between HC-12a® and DURACOOL 12a®?
DURACOOL 12a® has the same chemical composition as the HC-12a® formulation that was submitted for SNAP review as Hydrocarbon Blend B. Both HC-12a® and DURACOOL 12a® are different than the new formulation of HC-12a® in six-ounce cans. DURACOOL 12a® is the registered trademark of Duracool Limited, the Canadian company that has manufactured DURACOOL 12a® since 1997. Duracool Limited and OZ Technology, the manufacturer of HC-12a®, are separate, unrelated companies with their own manufacturing facilities and distribution mechanisms.
* What is the legal status of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®?
It has been illegal since July 13, 1995 to replace CFC-12 with the HC-12a® formulation that was submitted for SNAP review in any refrigeration or A/C application other than industrial process refrigeration. The same prohibition for OZ-12® took effect on April 18, 1994. Because DURACOOL 12a® has the same chemical composition as the HC-12a® formulation that was submitted for SNAP review (i.e., Hydrocarbon Blend B), DURACOOL 12a® is also subject to the same restrictions.
HC-12a®, as reformulated to meet DOT requirements, is not the same as Hydrocarbon Blend B and has not been submitted for SNAP review. OZ Technology is therefore prohibited from marketing this blend as a substitute for any ozone-depleting substance. In addition, any use of this blend as a substitute for CFC-12 or any other ozone-depleting chemical, in industrial process refrigeration or any other refrigeration or A/C end use, is prohibited under the Clean Air Act.
Since HC-12a® as submitted for SNAP review, is chemically different from HC-12a®, as reformulated to meet DOT requirements, and since it has a different legal status under the Clean Air Act, users of any substance marketed as HC-12a® should be aware of which HC-12a® they have purchased.
Note that the Clean Air Act does not regulate the use of any of these hydrocarbon refrigerants when they are used as replacements for non-ozone-depleting chemicals such as HFC-134a. However, many states prohibit using flammable refrigerants in motor vehicles, regardless of which original refrigerant was used in the vehicle.
* What is EC-12a and what is its legal status?
Because it has not been submitted for review under the SNAP program, EPA is not aware of EC-12a's chemical composition. EC-12a is not legal to sell or use in any refrigeration or A/C end-use as a substitute for CFC-12 or any other ozone-depleting refrigerant, because it has not been submitted for SNAP review.
* May hydrocarbon refrigerants be used to replace CFC-12, commonly referred to as "Freon® ," in cars?
No. It is illegal to use hydrocarbon refrigerants like HC-12a® and DURACOOL 12a® as substitutes for CFC-12 in automobile or truck air conditioning under any circumstances.
* How did EPA make this determination?
The Clean Air Act, as amended in 1990, required EPA to establish a program to review substitutes for ozone-depleting substances, including refrigerants. EPA's Significant New Alternatives Policy (SNAP) program carries out this mandate. Manufacturers of substitutes must submit information to EPA about the products, including ozone depletion potential, global warming potential, and toxicity and flammability data. EPA then compares these characteristics to both the refrigerant being replaced and the other available substitutes.
Most refrigerants submitted to EPA for review under SNAP have been found acceptable, often subject to certain conditions. A full list of alternatives is available online. In particular, several refrigerants have been listed acceptable for use as CFC-12 substitutes in motor vehicle air conditioning, subject to certain conditions on their use. Each acceptable alternative refrigerant has been demonstrated to a) be safer for human health and the environment than the original refrigerant, and b) pose a level of risk similar to that of other acceptable alternatives.
Flammable refrigerants pose a special challenge, because air conditioning and refrigeration systems in the US have been designed to use nonflammable refrigerants. They are not designed to protect users, service technicians, and disposal personnel from the possibility of fire. Therefore, the use of flammable refrigerants in existing systems may pose a risk not found with nonflammable fluids.
Although new systems may be designed to provide that protection, they are not specifically designed so today. Demonstrating that a flammable refrigerant can be used safely in current systems, whether existing or new, requires a comprehensive, detailed, scientifically valid risk assessment. EPA has required a risk assessment for flammable refrigerants since the inception of the SNAP program in 1994. An assessment must address potential leak scenarios such as collisions, servicing errors, and disposal procedures. In addition, it must consider ignition sources ranging from cigarette lighters or matches to sparks caused during a collision.
OZ Technology has submitted reports that it states demonstrate the safety of using OZ-12® and HC-12a® in systems not designed to use such flammable refrigerants. However, after careful review of each document, EPA determined that none of the reports represented valid a risk assessment. Until such assessments are performed, EPA believes that flammable refrigerants like HC-12a®, OZ-12® and DURACOOL 12a® may pose potential risks not present when using nonflammable refrigerants. For these reasons, EPA does not allow the use of HC-12a®, OZ-12® or DURACOOL 12a® as substitutes for CFC-12 outside of industrial process refrigeration. (Note that HC-12a®, as reformulated to meet DOT requirements, is not permitted to be sold or used as a substitute for ozone-depleting chemicals in industrial process refrigeration, since it has not been submitted to SNAP for review.)
* Why is it legal to use hydrocarbon refrigerants as CFC-12 substitutes in industrial process refrigeration, but not elsewhere?
EPA has not yet received data that adequately address the safety issues of hydrocarbon refrigerants in applications other than industrial process refrigeration. Flammability risks depend on the type of refrigeration or air-conditioning system. Industrial process refrigeration, for instance, does not include air conditioning, which pipes refrigerated air directly into occupied areas. Industrial process refrigeration generally refers to complex customized appliances used in the chemical, pharmaceutical, petrochemical and manufacturing industries. Direct risk to human health is reduced in industrial process refrigeration; for example, access to areas near the system is typically restricted. In addition, other regulations exist to protect the safety of industrial workers.
EPA will review any additional material that is submitted under SNAP regarding the safety considerations of using hydrocarbon refrigerants in systems other than industrial process refrigeration.
* Gasoline and brake fluid are flammable, but they're allowed in cars. Why not hydrocarbon refrigerants?
Because EPA has been directed by Congress, under the SNAP program, to consider the safety aspects of alternative refrigerants for CFC-12 (as well as their environmental characteristics), it is necessary to address the safety aspects of using a flammable refrigerant in motor vehicle A/C systems originally designed for CFC-12, before that refrigerant can be approved.
There are good reasons why gasoline and other fluids may be used safely while the use of hydrocarbon refrigerants in A/C systems may not be safe. Gasoline and other flammable substances are used in systems designed specifically for flammable fluids. A gas tank is deliberately placed in the middle of the rear part of a vehicle to protect it against collisions. Air conditioner condensers, in contrast, are placed at the very front of the car to maintain good air flow. Unfortunately, this location means that condensers may be punctured during a front-end collision. Another difference is that unlike gasoline lines, air conditioners include lines that provide cooling directly to occupied areas -- in this case, passenger compartments. Flammability risk is extremely dependent on the specific system being considered; the simple presence of other flammable fluids in a car does not address the safety of using hydrocarbon refrigerants in an automobile air conditioner.
* Is sale of hydrocarbon refrigerants legal?
Sale of subtitute refrigerants listed under the SNAP program is not regulated under SNAP. However, statutes and regulations issued by other federal, state, or local agencies may control the sale of these products, including illegal advertising.
* Since the autoignition temperature of HFC-134a is lower than that of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a®, doesn't that mean that HFC-134a is more flammable than these hydrocarbons?
According to both Underwriters Laboratories and the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE), the main standard-setting body for refrigerants in the U.S., hydrocarbons are flammable materials. Flammability, as defined by the American Society for Testing Materials (ASTM) E-681 standard test procedure for refrigerants, means that a substance will ignite at atmospheric pressure when mixed in some concentration in air at normal temperature and pressure. The minimum and maximum concentrations at which ignition will occur are called the lower and upper flammability limits in air. Hydrocarbons, like the components of HC-12a® and DURACOOL 12a®, become flammable at concentrations as low as 2% by volume. These values are well-established in published literature.
Autoignition temperature is a distinct measure from flammability limits in air. Specifically, this test measures the temperature at which a substance will spontaneously ignite, without any external ignition source like a match or lighter.
Certain documents claim that because the autoignition temperature of HFC-134a is below 750 degrees Celsius (1382 degrees Fahrenheit), it is flammable, and because the autoignition temperature of hydrocarbon refrigerant blends such as HC-12a® is above 750 degrees Celsius, it is nonflammable. However, this statement misrepresents the procedure used by Underwriters Laboratories to classify refrigerants.
UL first examines whether a refrigerant burns in air at some concentration and normal pressure and temperature. If it does ignite under these conditions, it is classified as flammable. Hydrocarbons, like the components of HC-12a® and DURACOOL 12a®, are classified as flammable. (Note that hydrocarbon refrigerant manufacturers recognize that their products are flammable, and label containers for those products with the word "flammable.")
If a refrigerant is not classified as flammable as a result of this test procedure, UL then uses the autoignition temperature to distinguish between practically nonflammable refrigerants (meaning the autoignition temperature is below 750 degrees Celsius) and nonflammable refrigerants (meaning the autoignition temperature is above 750 degrees Celsius). HFC-134a does not ignite, regardless of concentration, at atmospheric temperatures and pressures. This means that at atmospheric pressures and temperatures, if a can of HFC-134a is opened and a lit match is placed in front of the can, the HFC-134a will extinguish the match. HFC-134a is classified by UL as practically nonflammable because its autoignition temperature is below 750 Celsius. Note that UL lists most alternative refrigerants as practically nonflammable. HCFC-22, the refrigerant used in most home air-conditioning, is also classified as practically non-flammable.
* What is a "sham retrofit" of a motor vehicle A/C system?
EPA does not regulate the use of hydrocarbon refrigerants such as HC-12a® and DURACOOL 12a® as substitutes for HFC-134a in motor vehicles. Certain materials have circulated claiming that by first converting a system from CFC-12 to HFC-134a, the system may then be converted to use a hydrocarbon refrigerant without violating the original prohibition against using hydrocarbons as substitutes for CFC-12. Thus, the question arises about the definition of a legitimate retrofit. This definition hinges on two distinct principles: complying with the conditions placed on using HFC-134a under the SNAP program, and the intent of the retrofit.
In accordance with the SNAP rules, a retrofit from CFC-12 to HFC-134a must meet certain requirements. The CFC-12 must be completely recovered in accordance with regulations issued under section 609 of the Clean Air Act. Fittings designed for use with HFC-134a must be permanently attached to the system. These fittings mechanically prevent the mixing of HFC-134a with CFC-12 and other refrigerants. Finally, the system must be labeled, and the label must contain detailed information as described by the SNAP rule. Some vehicles also require the installation of a compressor shutoff switch. Performing these activities complies with the letter of the SNAP regulations.
Even such compliance may not, however, indicate a legitimate retrofit. For example, HFC-134a should be used with a different lubricating oil from CFC-12; if the lubricant is not changed, the air conditioner will not work. Similarly, a vehicle must be charged with the correct amount of HFC-134a in order for the air conditioner to work. Failure to take these steps indicates that the technician does not truly intend to convert the vehicle's air conditioner to work with HFC-134a, and the subsequent installation of a hydrocarbon refrigerant such as HC-12a® or DURACOOL 12a® may violate the prohibition against using hydrocarbon refrigerants as CFC-12 substitutes.
Other indications of a sham retrofit also exist, including the timing of the retrofit. In general, if a car arrives in a repair shop containing CFC-12 and leaves containing a hydrocarbon refrigerant, it is likely that it underwent a sham retrofit, regardless of what actually occurred in the shop. Generally, if HFC-134a is charged into a system and then immediately removed, such a temporary retrofit to HFC-134a was likely intended solely to allow the use of HC-12a®, DURACOOL 12a®, or other hydrocarbon refrigerant in a car designed to use CFC-12. EPA is currently investigating several complaints, and believes indications such as those described above support finding a Clean Air Act violation.
* May hydrocarbon refrigerants be vented?
No. The Clean Air Act prohibits the venting of any refrigerant during the service, maintenance, repair, or disposal of air conditioning and refrigeration systems. When working on a system containing a hydrocarbon refrigerant such as HC-12a® or DURACOOL 12a®, the technician must recover the refrigerant into a suitable container and safely dispose of it.
* What other regulations restrict the use and handling of hydrocarbon refrigerants?
In addition to the prohibition on use described above, and the federal law banning the venting of all refrigerants, there are also state and local statutes and regulations that relate to certain uses of hydrocarbons. As of the printing date of this fact sheet, EPA is aware that the following states prohibit the use of flammable refrigerants in automobile air conditioners: Arkansas, Arizona, Connecticut, Florida, Idaho, Indiana, Iowa, Kansas, Louisiana, Maryland, Nebraska, North Dakota, Oklahoma, Texas, Utah, Virginia, Washington, Wisconsin, and the District of Columbia.
Local fire codes also often restrict the storage of flammable materials. In addition, other federal, state, and local regulatory agencies may have regulations related to flammable refrigerants. Check with these authorities for more information.
* Are there other refrigerants that can replace CFC-12?
Yes. Lists of alternatives in other sectors are available online and from our hotline at 800-296-1996. In addition, the fact sheet titled "Choosing and Using Alternative Refrigerants for Motor Vehicle Air Conditioning" lists all SNAP-reviewed motor vehicle refrigerants and conditions on the use of those listed as acceptable.
* Are there any advantages to using flammable hydrocarbon refrigerants?
Many flammable refrigerants offer potential energy efficiency savings, lower global warming potentials, low toxicity, and low cost. EPA believes that, with responsible development, flammable refrigerants have a role to play in the transition away from ozone-depleting substances. However, such development must adequately address safety concerns associated with manufacturing, use, servicing, and disposal of these new products. EPA is aware of several successful uses of flammable refrigerants, and welcomes future development of systems designed to be used with them.
The primary drawback to the use of flammable refrigerants today is that most existing systems are not designed to protect people from that flammability. In order to find a flammable refrigerant acceptable, EPA requires the completion of a risk assessment to determine the additional hazard posed by that flammability and necessary steps to mitigate any additional hazard. EPA believes hydrocarbons and other flammable refrigerants offer the potential to be good substitutes for ozone-depleting refrigerants. The best possibilities exist in the design of new equipment that includes safety features to protect against a fire or explosion. Several such systems are now being sold and developed around the world. EPA has always encouraged U.S. businesses to consider using hydrocarbon refrigerants in such newly designed systems.
* Has EPA found any flammable refrigerants acceptable under SNAP?
EPA found the flammable refrigerant HFC-152a acceptable for use in new household refrigerators and freezers. This determination was based on a detailed assessment of the risks posed by this flammable refrigerant in this particular application. Note that HFC-152a, which is a single chemical rather than a blend, is not a hydrocarbon. The fact that HFC-152a was found acceptable in refrigerators cannot be read as encompassing all hydrocarbon or other flammable refrigerants in all end-uses. A risk assessment relates only to the specific end-use and refrigerant.
* Is it legal to replace HFC-134a in a motor vehicle with hydrocarbon refrigerants such as DURACOOL 12a® and HC-12a®?
In certain circumstances, the replacement of HFC-134a in a motor vehicle with hydrocarbon refrigerants might be permitted. At a minimum, in order to avoid violating the Clean Air Act, the motor vehicle A/C system must have either been originally designed for use with HFC-134a refrigerant, or must have been previously retrofitted from CFC-12 to HFC-134a refrigerant, AND no sham retrofit must have occurred to convert the system to the hydrocarbon refrigerant. In order to avoid violating other laws, the replacement of the refrigerant must not violate any state or local prohibition on the use of flammable refrigerants in motor vehicle A/C systems.
The following 19 states ban the use of flammable refrigerants such as HC-12a® and DURACOOL 12a® in motor vehicle air conditioning, regardless of the original refrigerant: Arkansas, Arizona, Connecticut, Florida, Idaho, Indiana, Iowa, Kansas, Louisiana, Maryland, Nebraska, North Dakota, Oklahoma, Texas, Utah, Virginia, Wisconsin, Washington, and the District of Columbia.
EPA and hotline staff will not, based solely on facts given in a phone call or letter, determine the legality under the SNAP program of using a hydrocarbon refrigerant in a motor vehicle retrofitted to use HFC-134a, because the determination depends on many factors, including the nature of the retrofit from CFC-12 to HFC-134a, the reason for the retrofit, and the exact procedure and timing involved.
If you plan to change a car from HFC-134a to a hydrocarbon refrigerant such as HC-12a® and DURACOOL 12a®, you should consider that auto manufacturers have stated that changing the refrigerant in new vehicles designed for use with HFC-134a will void the warranty and may damage the system. If the air conditioner on a new car or truck is not working, consult a qualified mechanic or your dealer.
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Print As-Is
Last updated on Wednesday, March 03, 2010
brcidd
08-18-2010, 11:25 AM
Has anyone been changing OTs or condenser? -- number one problem with condenser is that it CAN be plumbed backwards...be sure your compressor feeds the top of condenser...also I've seen two OTS in suburbans with rear air-- one in condenser outlt and one in behind the "Y" split to the rear onthe liquid line. Yours only needs the one behind the "Y" split......
cris2004
08-18-2010, 01:09 PM
Has anyone been changing OTs or condenser? -- number one problem with condenser is that it CAN be plumbed backwards...be sure your compressor feeds the top of condenser...also I've seen two OTS in suburbans with rear air-- one in condenser outlt and one in behind the "Y" split to the rear onthe liquid line. Yours only needs the one behind the "Y" split......
I did change the OT in front, but not the expansion valve. I'm sure my problem is in the rear air system, but that doesnt make me right. It is behind the 'Y', and was very clean.
I havent touched the condensor other than to clean the outside, it was clean beforehand.
I cant fault the new compressor at this time, since the system is behaving very much like before I changed anything. I most likely removed perfectly good parts on a system that worked well before this last time I drove the car.
A couple thing to clear: The new compressor has ICE32 in it, a lubricant thats supposed to stick to metal parts and reduce friction. I have the same amt PAG 150 as in the old system.
I agree there is a circulation problem, I need to get into the rear case and change the TXV. I just hate to do it if thats not a good suspect.
I did pull 24hg for more than two hours, had it off for only fifteen minutes (more than the book says), had absolutly no loss in vaac. 24HG is all I'm going to get at 3200 feet on a cloudy day here. It may be my gauge is off one or two but this is what I pull on everything here. I do apprecites the thought though, I may be overlooking something. The main beef is I have the similar result as with the original parts in a once working system.
I kept pretty good notes on AC performance since buying the Suburban new in 98.
At the last install, I had 28 low and 325 high at 1500 RPM, 38 degrees with front only on and vent speed on low, at 105 degrees outside!
With the rear on, vent temps would move up to 44.
Also, I had 42-44 degrees cruising down the highway across the Navajo nation at 111 outside. The car color doesnt matter in the shade, (as in my working garage) but it is a real bear to cool when sitting in the sun.
Outside temps can be high when recirculating the inside air. I use the original fan with clutch and a powerfull aux fan so I can pull cold temps at idle, in a parking lot at over 100 degrees outside. (dear old dad can't always go in to shop with his wife when I'm the chauffer)
The old compressor did indeed rattle a bit, but still worked. I see now it was getting abused. I don't think I'm low on oil in the overall system, but I do believe the is a blockage is somewhere causing oil to collect. It just doesnt make enough sense.
I really appreciate the comments. Since the new parts are behaving a lot like the old system, I see I havent fixed anything, but I don't think I've degraded anything either.
I'm going to get to swapping the TXV.
The system was very clean. Is there any value to flushing the rear evap or is that asking for a problem? Would it be advisable to push just clean air through the parts when the TXV is off just to see if it passes well?
Is there a clear cut test for the rear TXV?
Thanks again
I did change the OT in front, but not the expansion valve. I'm sure my problem is in the rear air system, but that doesnt make me right. It is behind the 'Y', and was very clean.
I havent touched the condensor other than to clean the outside, it was clean beforehand.
I cant fault the new compressor at this time, since the system is behaving very much like before I changed anything. I most likely removed perfectly good parts on a system that worked well before this last time I drove the car.
A couple thing to clear: The new compressor has ICE32 in it, a lubricant thats supposed to stick to metal parts and reduce friction. I have the same amt PAG 150 as in the old system.
I agree there is a circulation problem, I need to get into the rear case and change the TXV. I just hate to do it if thats not a good suspect.
I did pull 24hg for more than two hours, had it off for only fifteen minutes (more than the book says), had absolutly no loss in vaac. 24HG is all I'm going to get at 3200 feet on a cloudy day here. It may be my gauge is off one or two but this is what I pull on everything here. I do apprecites the thought though, I may be overlooking something. The main beef is I have the similar result as with the original parts in a once working system.
I kept pretty good notes on AC performance since buying the Suburban new in 98.
At the last install, I had 28 low and 325 high at 1500 RPM, 38 degrees with front only on and vent speed on low, at 105 degrees outside!
With the rear on, vent temps would move up to 44.
Also, I had 42-44 degrees cruising down the highway across the Navajo nation at 111 outside. The car color doesnt matter in the shade, (as in my working garage) but it is a real bear to cool when sitting in the sun.
Outside temps can be high when recirculating the inside air. I use the original fan with clutch and a powerfull aux fan so I can pull cold temps at idle, in a parking lot at over 100 degrees outside. (dear old dad can't always go in to shop with his wife when I'm the chauffer)
The old compressor did indeed rattle a bit, but still worked. I see now it was getting abused. I don't think I'm low on oil in the overall system, but I do believe the is a blockage is somewhere causing oil to collect. It just doesnt make enough sense.
I really appreciate the comments. Since the new parts are behaving a lot like the old system, I see I havent fixed anything, but I don't think I've degraded anything either.
I'm going to get to swapping the TXV.
The system was very clean. Is there any value to flushing the rear evap or is that asking for a problem? Would it be advisable to push just clean air through the parts when the TXV is off just to see if it passes well?
Is there a clear cut test for the rear TXV?
Thanks again
cris2004
08-25-2010, 09:19 AM
I did swap the rear x valve. I had to do it twice as the first four seasons POS leaked around the body's solder. I couldn't detect it on vacuum and ended up shooting a pound of freon to then hear it hiss. Like MT said, four seasons was a mistake.
The rear air does work 'better' now. The evap case gets cold and drips like crazy. This was not the case before. The rear vent temp is 45 on an evening with a temp of 90. I'm satisfied with that.
Unfortunately, the front air seem very much the same. 60 degree vent temps at 90 outside last night. I read when freon is low, the rear will work before the front. I added another pound for a total of 5 1/2 by my measurement, and it did improve.
I may not have an accurate weight on the freon unfortunately.
I ended up getting a new low Vaac gauger as mishalah had suggested I wasn't low enough. My old gauger did indeed read high, thanks. I pulled less than 28hg for a couple hours, and left it off, with a shut off to the pump closed, for nine hours and lost a pound or two. I re-vaced after getting home and filled.
I had 25/180 at 2000 rpm before adding the 'extra' pound, and 35/225 at 2000 after.
I guess its obvious I was wrong on the weight.
The muffler at the compressor that should be cold is only cool to the touch.
If I overcharge would the high side go up as the low side would?
Is there something I did wrong to make the front performance poor, or is it a case of a poor compressor and high expectations?
Any help is appreciated. I'll give it a drive today before heading out nine hours in the desert and mountains. I'm hoping the rear air will keep a deer from spoiling coming home!
The rear air does work 'better' now. The evap case gets cold and drips like crazy. This was not the case before. The rear vent temp is 45 on an evening with a temp of 90. I'm satisfied with that.
Unfortunately, the front air seem very much the same. 60 degree vent temps at 90 outside last night. I read when freon is low, the rear will work before the front. I added another pound for a total of 5 1/2 by my measurement, and it did improve.
I may not have an accurate weight on the freon unfortunately.
I ended up getting a new low Vaac gauger as mishalah had suggested I wasn't low enough. My old gauger did indeed read high, thanks. I pulled less than 28hg for a couple hours, and left it off, with a shut off to the pump closed, for nine hours and lost a pound or two. I re-vaced after getting home and filled.
I had 25/180 at 2000 rpm before adding the 'extra' pound, and 35/225 at 2000 after.
I guess its obvious I was wrong on the weight.
The muffler at the compressor that should be cold is only cool to the touch.
If I overcharge would the high side go up as the low side would?
Is there something I did wrong to make the front performance poor, or is it a case of a poor compressor and high expectations?
Any help is appreciated. I'll give it a drive today before heading out nine hours in the desert and mountains. I'm hoping the rear air will keep a deer from spoiling coming home!
Cusser
08-28-2010, 08:26 AM
I had 25/180 at 2000 rpm before adding the 'extra' pound, and 35/225 at 2000 after. Any help is appreciated.
Cris - I'm in Arizona like you. My Suburban is a 1994 so mine has a different compressor. That stated, my pressures are higher than yours, and at similar Arizona temperatures. At 2000 rpm my high side typically reads like 280 psi. So in your situation I would add ONE (and one only) 12-ounce can of R-134a. Remember to bleed air out of the gauge lines before adding.
Cris - I'm in Arizona like you. My Suburban is a 1994 so mine has a different compressor. That stated, my pressures are higher than yours, and at similar Arizona temperatures. At 2000 rpm my high side typically reads like 280 psi. So in your situation I would add ONE (and one only) 12-ounce can of R-134a. Remember to bleed air out of the gauge lines before adding.
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