air compressor kicks on and off

'95 Chevy Blazer. My latest problem: Air blows hot air. I bought gauge / freon fill kit. When I began, I noticed the air compressor kicking on and off. I checked the low side pressure where the freon is put in and when the comprerssor kicks in, pressure goes to almost 45, instantly compressor kicks off and pressue goes near 0. Cycle repeats over and over. Is this normal when just needs freon or do I have bigger problem. Thanks so much for any help.

'95 Chevy Blazer. My latest problem: Air blows hot air. I bought gauge / freon fill kit. When I began, I noticed the air compressor kicking on and off. I checked the low side pressure where the freon is put in and when the comprerssor kicks in, pressure goes to almost 45, instantly compressor kicks off and pressue goes near 0. Cycle repeats over and over. Is this normal when just needs freon or do I have bigger problem. Thanks so much for any help.

Is this a r-12 system or r134a and what kind of gas are you installing?

Somthing is wrong there. Be carefull . Are you sure you are tapped to the low side?
When compressor kicks in the low side should go down.
Get that one hose death trap can kit off of it and get the proper low and high side recharge gauge set on it. Like this.
http://www.ackits.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=AMA&Product_Code=66773

But Your biggest problem may be that death kit you are using.
If you have not added the stop leak stop right there.
If you have it may be all over with.
http://www.autoacforum.com/messageview.cfm?catid=2&threadid=15719

Wal Mart DEATH KITS

You cannot properly and safely recharge an air condition system with them.

The one side stop and go gauge does not tell you what your system is doing or is over charged or undercharged.
A overcharged or malfunction air condition system can reach over 500 lbs of pressure.
Enough to blow up that can or system and freeze you at first and the burn you or blind you and if any propane /butane in there blow and light you up.

The stop leak crap and who knows what kind of oil in the kits there will stop your system for sure.
Just like pouring super glue in it.
And some kits even contain freon with a butane mixer.
Good for a big blast.

If you are going to do it do it right and safe.
Here is what you need to start with.
http://www.ackits.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=AMA&Product_Code=66773

In the older days you could just throw in a can and go.
But over the years just adding freon is getting harder to do.
Newer systems have to have the correct amount of freon down to the ounces.
Most will need pumped down and vacuumed down and the right and amount of oil and a set amount freon charge installed to get the air to cool right and the system to last.
If an air condition is low there is usually a leak that needs fixed and also a lose of lubricating oil from system.
Also air and moisture enters a low system
If you are going to try to do it get the proper type air condition gauge set with the low and high side gauges.
Hook up the gauges and get a reading with compressor running at idle and at 2000 rpm on the high and low side.
Post back pressure reading and we can help you.
MT

The kit is from wal-mart r134a. I gave $27 for it. It has gauge to show highs and lows. It says the gauge made only to fit the low pressure fitting. I did not puncture the can to put any gas in. I think I will take the kit back and take it to a professional. Thanks!!!!!

The kit is from wal-mart r134a. I gave $27 for it. It has gauge to show highs and lows. It says the gauge made only to fit the low pressure fitting. I did not puncture the can to put any gas in. I think I will take the kit back and take it to a professional. Thanks!!!!!

That may be a good idea.
At least you did not put in the stop leak super glue stuff.
http://www.autoacforum.com/messageview.cfm?catid=2&threadid=15719
The one side gauge is not enough to check or safe charge the system.
If someting is bad the on system it can reach over 500 lbs of pressure high or even low side.
When charging or testing your air cond system you need to watch and get a reading on low and high at the same time.
Good luck and let us know how it goes.
MT

There is a low pressure cut off switch that turns off the compressor.

What you are seeing is normal.

Add some freon until it stays on all the time and then check the pressure.

There is a low pressure cut off switch that turns off the compressor.

What you are seeing is normal.

Add some freon until it stays on all the time and then check the pressure.

Welcome to your first post on AF.
In this case unless the poster posted the pressure reading backwards his system has a problem.
Just adding freon until the compresser stays on all of the time and without a low and high side gauge.
Is not the safe and proper way to recharge a air cond.
And the one hose stop and go gauge death kit with the super glue is a no no.
MT

Thanks.
Just an FYI...I have been doing this for over 10 years.

"Just adding freon until the compresser stays on all of the time and without a low and high side gauge"
I assume if he is working on his A/C unit he would have the prober gauges.

If he adds freon and it stays on his then checks the pressure it will probably be around 20-25 lbs when the compressor is running. This is normal.

Again... The low pressure switch is what is turning off the compressor.
It's supposed to work that way.







Welcome to your first post on AF.
In this case unless the poster posted the pressure reading backwards his system has a problem.
Just adding freon until the compresser stays on all of the time and without a low and high side gauge.
Is not the safe and proper way to recharge a air cond.
And the one hose stop and go gauge death kit with the super glue is a no no.
MT

The kit is from wal-mart r134a. I gave $27 for it. It has gauge to show highs and lows. It says the gauge made only to fit the low pressure fitting. I did not puncture the can to put any gas in. I think I will take the kit back and take it to a professional. Thanks!!!!!

Nothing wrong with topping off the refrigerant yourself.

Test pressure with the fan on high and the AC on MAX.

Once the level it up to snuff the cycling will stop.

But remember, it is normal for the AC compressor to kick on and off once in a while.

It is when it cycles on and off every 2-3 seconds that you have low refrigerant or the low pressure switch is shot.

Thanks.
Just an FYI...I have been doing this for over 10 years.

"Just adding freon until the compresser stays on all of the time and without a low and high side gauge"
I assume if he is working on his A/C unit he would have the prober gauges.

If he adds freon and it stays on his then checks the pressure it will probably be around 20-25 lbs when the compressor is running. This is normal.

Again... The low pressure switch is what is turning off the compressor.
It's supposed to work that way.

Reread the posters post.
He was going to use a Wal mart death kit.
And the pressure reading he posted was not right.
Just adding freon untill the compressor quits kicking on and off or using one of them One hose stop and go gauges is not the proper or safe way to recharge air cond systems.
You need one of these to start with.
http://www.ackits.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=AMA&Product_Code=66773

http://www.ackits.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=AMA&Product_Code=DIY-STARTER1

http://www.ackits.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=AMA&Product_Code=DIYADVANCE

MT is right. When the compressor kicks on, the pressure on the low side is suppose to drop. If the system is low of refridgerant, when the pressure drops too low the compressor will kick off and the pressure on the low side will rise. The compressor will then kick back on until the pressure drops again, and the cycle continues. This short cycling would indicate a low refridgerant condition. However in this case, as MT pointed out, the system's pressure readings are the opposite of what they should be. This is an indicator that something may be wrong with the system, and simply adding more refridgerant may cause damage to the system or the operator.