Re: AUTO AC suction pressure low

Don wrote:

On Fri, 23 Jun 2006 22:07:21 GMT, Jeff <dont_bug_me@xxxxxx> wrote:


I have an '88 New Yorker that has been converted to 134.

I've vacuumed out the system and added two cans of R134,


A can is 12 ounces x 2 = 24 ounces. Capacity of this system before
conversion is about 40 ounces. Subtract about 15% for change of
refrigerant type and the system is still badly undercharged. You
would be a hair over with a third can.

There could be a bad expansion valve as well.


New expansion valve.

I had been having trouble. Seemed like high head pressure as the clutch blew on the compressor. So I put in what looked like a good used compressor and a new expansion valve. I blew out the evaporator and condensor with compressed air as I had way to much dye in it. The condensor definitely had more "resistance" to flow, but did not appear blocked. Not sure what to expect...

I'll add a can in the morning and see what gives. Should only be POE and mineral oil and whatever was left of the can of dye as I added the whole can! (Had a compressor that leaked at the clutch seal).

Jeff


Don
www.donsautomotive.com


this worked fine for a while but stopped cooling after 15 minutes. System is still charged.

Looking at the suction side I see a vacuum, this slowly goes away after a minute and the AC clutch kicks in and it runs back down into a vacuum.

I suspect that I must have a blockage somewhere. Could a drier do that? Or is this more likely to be a condensor or something else. How do you tell?


Drier should have equal temperature on the lines in and out. A
restriction causes a cold area from that point on. That is what the
expansion valve or tube does.


Anyone have that chart of low side and high side pressures and what the trouble may be?


Original specs don't mean much after a conversion has been done. But look for 15-25 PSI low side, 250-350 high side at 90* ambient,
1750 rpm.

Don
www.donsautomotive.com


Jeff


.

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