AC Pressure

[czm400r]

Is there a differance in cooling speed and Temp. if the system is charged at 25# vs. 45# Both are within the "Safe" range per my guage.

[BlazerLT]

cooling speed and temp?

I don't get what you are saying.

[drdd]

Perhaps what is trying to be asked is what I asked (without reply) in the Jimmy forum. That is, what is the relationship between AC-system-pressure and refrigerant level (amount). ??

In other words, is it possible to have a high AC system pressure while at the same time having little or no refrigerant in the system/

Does adding 134refrig automatically increase a pressure reading?


Of course, consider all the "vice-versa"s ............ ??????????????

Originally Posted by BlazerLT

cooling speed and temp?

I don't get what you are saying.

[blazinLT]

You will increase system pressure by adding additional freon.
As far as a relationship between system pressure and amount= NO!
But, there is a pressure/temperature relationship you should be concerned with. (R134A @ 30lbs of suction pressure is 35 degrees)
I would charge vehicle accordingly for 30lbs suction with the motor revved up and a box fan or squirrel cage blower blowing across the condensor. This will mimic real world conditions as your suction pressure drops during driving.

[czm400r]

I guess what I am asking is, will the car produce colder air sooner if the pressure in the system is 45# vs. 25#?

[xtrememeasures10]

A good cooling system should have a 20degree drop. for instance if you take the temp in your car and its 100. your air coming out of the vents should start out at 80. it will continue to drop but there should be a difference of 20 degrees b/t the air in the blower motor and the air coming out of the evaporator fins.

[tom3]

The lower the pressure the lower the temperature, unless the low pressure is a result of low refrigerant charge, then you have less capacity, obviously, because of the lack of refrigerant. So if you can adjust your low pressure cut out to a lower pressure with a fully charged system, yes you will have a cooler air temp.

[BlazerLT]

you get a gauge and test to see if the pressure is within the safe pressure zone on the GAUGE with the AC on MAX with the fan on full blast.

[blazinLT]

Yes, it will be colder for awhile until it freezes up!
R134A @ 25lbs suction pressure is 29 degrees, remember
water freezes @ 32deg. So.........set the suction @ 30lbs
and roll on!