r134 recharge, warm a/c no cycling

[norbs]

Just put in R134, now the compressor runs continuous, and the air is warm 60 on a 80 degree day. The compressor is new and orffice tube, and dryer. Has anyone else had there compressor never shut off?


thanks norb

 

[tjthorson]

Well, did you vacuum it down to 30inches for at least 20 minutes before filling? What did you fill it to? WHat is the high/low side pressures when the compressor is running?

A lot of variables there.....

 

[norbs]

yes we did that and put in 80"% of freon with the snap-on machine. At idle the low pressure side was 40 rev it up to 2k its 32 on a 80 degree day. High side gauge wasn't working

 

[tc86gn]

Did you put in the correct amount of oil in the compressor and dryer? Heck if I lived in Canada I wouldn't even bother with it.

 

[tjthorson]

Hmmm. And it held a vacuum with the pump off, without dropping off? You replaced all the right parts. I would get a working high side gauge. I bet the head pressure is through the roof, indicating air in the system. Maybe something wrong with the freon used? Contaminated?

Its not working because it doesn't like you. Low side pressure looks good. Gotta check the high side. I bet you will end up vacuuming it down again and refilling though..... Sorry!

 

[Mr.Buick]

Retrofit AC 134A

Once your pressures and temps are satisfactory, (30 low/180 high) approx. you will have to adjust the compressor cycling switch to come on at a lower pressure than it did with the R12. You want between 19-21 psi. You can reduce the cycling pressure by turning the screw beneath the connector on the cycling switch counter clockwise. The cycling switch is located on the side of the accumulator. You can purchase a freon guage to check amount of charge in the system for about $5.00, looks like a tire air pressure tester. Hope this helps you. Roger Flint (Mr. Buick)

 

[TurboJim]

Feel both heater hoses to see if the heater control valve is leaking.32-40psi on the low side means the evaporator is cold.

 

[tc86gn]

Also check the adjustment on the temp door in the box.

 

[salvageV6]

The best I could do yesterday was 52 degrees on a hot 94 degree day.

Right at the vent outlet with the second EGT input on my meter.

Worked well after a good 10 minute drive on the highway.

 

[norbs]

I will try those suggestions, and get someone else to refill it, aren't u supposed to add freon, until it gets colder and and colder and then stop when the temp stops dropping? I cant get the low side under 30, this means the compressor will never cylce?

 

[Steve Wood]

If the compressor is running continuously, do not add more freon, it will make it hotter. You need to check the high side pressures to be sure the compressor is doing its job.

 

[TurboJim]

Originally posted by norbs
I will try those suggestions, and get someone else to refill it, aren't u supposed to add freon, until it gets colder and and colder and then stop when the temp stops dropping? I cant get the low side under 30, this means the compressor will never cylce?

Its dumb comments like that made people tire of you in BuickGN. You add freon (or refrigerant) until the pressures are correct, OR you STOP if theyre not coming into the right.

I'll tell you again. R12 system with R134a in it, on a 90* day you want 37-42 on the low side and 225-250 on the high side. Just rule of thumb, and your pressures may vary by +/-5psi on the low and 10+/- on the high. If you have those pressures, and 60* vent air, theres a problem with the heater control valve, or some other reason the air is getting heated before coming out of the vents.

 

[John Larkin]

L-O-fookin-L! Jim, hehe.