System low on refrigerant won't take charge

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Ken David
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Joined: Wed Jun 20, 2018 2:06 pm

System low on refrigerant won't take charge

Postby Ken David » Wed Jun 20, 2018 2:11 pm

It has been a while since I posted (never on this new forum-had to create a new account from the older ackits.com forum) Anyway I have an A/C issue that I was hoping somebody could help me get started in the right direction. I have been able to successfully repair some other vehicles and actually did a R12 to R134a conversion (parts and supplies from ackits.com) but this situation puzzles me. 1998 Pontiac Transam 5.7L ~30K miles that does not get driven much, seemed like the A/C has not been cooling like it should the last couple year. I expected a slow compressor main seal leak due to non-use. Finally got the gauges on today (compressor is engaging). ~90F Ambient temp Low side 25 and high side ~200 attempted to put in a couple ounces of R134a but system will not take any refrigerant (charging low side, gas, can). Evaporator inlet cold (not super cold) and sweating, outlet warm. Any ideas would be a great help. From the basics I know I really thought this issue sounded like low refrigerant. Thanks in advance.
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Cusser
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Joined: Sun Apr 24, 2016 6:29 am

Re: System low on refrigerant won't take charge

Postby Cusser » Wed Jun 20, 2018 4:43 pm

Make sure your can of R134a does not contain ANY sealer !!!

Guess #1: your charging hose fitting is not depressing your low side valve

Guess #2: try misting the condenser in front of car with a garden hose/water while you try to add refrigerant.
Ken David
Posts: 4
Joined: Wed Jun 20, 2018 2:06 pm

Re: System low on refrigerant won't take charge

Postby Ken David » Wed Jun 20, 2018 5:43 pm

Cusser wrote:Make sure your can of R134a does not contain ANY sealer !!!

Guess #1: your charging hose fitting is not depressing your low side valve

Guess #2: try misting the condenser in front of car with a garden hose/water while you try to add refrigerant.



Thanks for the reply Cusser!! Just pure R134a no sealer, don't want to create more issues or any real issues that is for sure! My low pressure port connection is suspect (reading were staying high when I attempted to charge through the low pressure side and after I shut off the flow of refrigerant- I had to disconnect and reconnect to relive pressure to obtain normal readings. I am wondering if I will need to get a replacement low side quick connect or possible replace the Schrader valve? I'll give it a try again with misting the condenser.....thanks again for the tips!!

In addition thanks to this forum I was wondering if my pressures indicate a possible orifice obstruction? The low pressure I know is on the low side for the temps however the high side is closer to normal than low? I would expect it to be lower if low on Freon at 90F?
Ken David
Posts: 4
Joined: Wed Jun 20, 2018 2:06 pm

Re: System low on refrigerant won't take charge

Postby Ken David » Thu Jun 21, 2018 6:02 pm

Update:

Decided to give it another try slightly cooler temps (high humidity) ~80F

Low side ~25 PSI and High Side climbs up to almost 275 but drops to 150 when the fans kick on (cycle on and off). I tried to spray the condenser (made a mess) since there is no access in the front of the vehicle and when I spray in the fans the high side does drop a little. Evaporator input cold to the touch and sweating (not super cold) output warm. Vent still blowing warm air. Still won't take a charge and I am stumped.

I guess my next step is to purge the system, pull a vacuum and attempt to add the required 1.5 lbs unless by chance somebody has any tips? It would greatly be appreciated. Thanks
Ken David
Posts: 4
Joined: Wed Jun 20, 2018 2:06 pm

Re: System low on refrigerant won't take charge

Postby Ken David » Mon Jun 25, 2018 12:24 pm

Update2

Decided to take it to an A/C shop and get it filled correctly by weight (even though I prefer servicing my own vehicles).

System was low ~1lb (1.5 lb total capacity).....pressures looked similar to what I was seeing, they evacuated, pulled a vacuum, replaced any oil that came out and charged to proper spec. Did a visual inspection (only thing they noticed was the Low side schrader valve was slightly loose). It is possible the A/C has never been serviced (pretty sure previous owner did not....so for 12 years or so at least it has not been touched). Anyway not quite sure why it would not take a charge for me but at least for now it is blowing cold.
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Cusser
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Re: System low on refrigerant won't take charge

Postby Cusser » Mon Jun 25, 2018 3:16 pm

Ken David wrote:Decided to take it to an A/C shop and get it filled correctly by weight (even though I prefer servicing my own vehicles).

System was low ~1lb (1.5 lb total capacity).....


Hopefully shop put some UV dye in the system since it was low, to help find any future leak/lack of cooling.

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