AC question

I just converted my truck to R134A... it cools well (we'll see when it's not 65 out).. but do I check the system pressure when the compressor is running or when it's not? I've got 45psi when it's not running and 27 or so when it's running with a charge of about 32 OZ (two 12oz r134 cans and part of another). am I good or do I need to get the comp. running pressure higher?

thanks, Bret

Reply to
Bret Chase
Loading thread data ...

Bret,

You need to test the low side pressure with the compressor on, engine at cruising RPM (around 2,000 RPM). You've got it undercharged right now if it's running 27 psi @ idle.

On a 65* day, you'll want her running 27-30 psi @ 2k RPM, which will put you at 40psi or so @ idle.

Doc

Reply to
"Doc"

I kinda figured it was low, but the instructions didn't say anything about the compressor. I didn't feel like asking the moron at the shop who vac'd it out... the dipshit took out my shraeder valves and told me the adapters had valves in it... golly gee wonder what the hissing sound is while the machine was running.. anywhoo.... it's nice to have AC again esp heading back south.

-Bret

Reply to
Bret Chase

You might also consider adjusting the low pressure cutout switch to a lower pressure to get colder air. Depending on your rig. A great forum for A/C is

formatting link
. They have helped me =tremendously in the past. Good Luck

Reply to
Mastermech

pressure to get colder air. Depending on your rig.

I've got 45F air out of the vents, I'm afraid if it was much colder I'd risk freeze ups.

-Bret

Reply to
Bret Chase

Which means, if you're lucky, the air at the vents will be 80 when it's 95 outside.

lower pressure to get colder air. Depending on your rig.

Reply to
Curmudgeon

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.