Date: Tue, 19 Apr 2005 18:29:44 -0700
Reply-To: TJ Hannink <tjhannink@YAHOO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: TJ Hannink <tjhannink@YAHOO.COM>
Subject: Re: 1985 westy a/c problem-insuficent cooling r-12 system
In-Reply-To: 6667
Content-Type: text/plain; charset=us-ascii
The 220 psi high side is way too high for an 80F day, in fact, R-12 shouldn't go above 200 psi period. The 45 psi low side also seems very high. Reduce your pressures, start at around 30 on the low side.
For reference, I look for 200 psi high/30-35 psi low with R-134a in 90F ambient temperature in both Goldibox and the 'Lodge.
Good luck,
TJ
roger sisler <rogersisler2000@YAHOO.COM> wrote:
Hello,for about a year now, I have been trying to get my a/c working.Lucked out here in DC with a cool summer last year.I have kept it R-12. A total rebuild was done last fall.I got a new Sanden 508, a rare R-12 expansion valve, and reciever-dryer. 4 cans of freon.I am getting insufficent cooling. I'll explain whats been done and what the gage readings are.If any a/c people are out there, it would make my day for several months if you could diagnose the problem. I got this van with the usual bad a/c system. There is no low pressure cut out switch on the 85, so the compressor continued to run without freon in the system,and ran out of oil.By the way, anyone who wants a cut out switch to install in the high side,ask Ron at BD to get some from Larry,at South East Air.These switches will prevent the described destruction of your compressor($10). Strange noises were coming from the compressor, and it was declared dead.I flushed all the hoses and components with mineral spirits,and a
flush gun.The condenser fins were cleaned with proper product..These parts were assembeled with new o-rings(green).I removed the evaporater cabinet from the ceiling and installed all new foam sealing strips.Cleaning everything in general,and reinstalling.I got a R-12 expansion valve from Classic Auto Air , in Tampa Fla.This is the origional CCA valve that came with the van when new.It was 30 years old, but never used.Probably fits a early 70's ford.The threads on the dealer installed a/c are american. I think most systems that are repaired and kept R-12 today, dont work so well, as a 134a expansion valve is usually installed,now that R-12 stock is almost gone. Today, it was pretty warm, and I thought I could get some accurate gage readings.It was 75 degrees today.Here are the conditions and readings.Air across the evaporator changes tempature by 10 degrees.Incoming air was 80 degrees and the outlet air was 70 degrees.Not near enough.Normal is about 20 degrees
difference..Condenser fan is working.The high side reading is 220psi @2000RPM.Low side is 45 psi.It looks like my high side is normal and the low side is high.The sight glass is clear w/no bubbles. No frosting at the expansion valve, nor sweating.I think the compressor is good. 220 psi is right on the money.Trouble shooting charts say that I could have an overcharged system.Dont believe that is the problem , as I charged in 48 ounces.This is in the ball park for a 85 westy. One test that I didnt do to determin overcharge is to run the system for 10 minutes and then pull the plug on the compressor.If bubbles take more than 45 seconds to appear in the site glass, I have an overcharge.I still got that card to play. Another possiability is the expansion valve stuck open.I sprayed liquid refrigerant on the capillary tube of the sensor bulb, and got a reduction in low side pressure as the valve closed down.The reading was then 30psi. Valve good-unless-super heat setting has been messed
with somewhere during the valves 30 year life.Could this cause an insuficent cooling condition? About 40 degrees of superheat? Dont usually find strange problems like this covered in trouble shooting guides.No one dares to touch this setting before installing a new valve. I dont think a restriction exists in the reciever-dryer. As I charged the system, I could see refrigerant rushing past the sight glass.I did blow through the reciever-dryer just before I installed it to be sure no restriction was present. Each hose and component was flushed seperately ,and none had any restrictions.The R-12 was new ,in 12oz cans.4 of them.I know the condenser is dinkey, but it is stock, and it is clean. Is this maybe a expansion valve with too little superheat(once again, out of adjustment)? Could the valve be flooding the evaporator,and be causing insufficent cooling? Would this still allow normal high side pressures? I have run the compressor for about 7 or 8 hoursand havent killed it yet. Well,
I'm out ideas and dont know what to do. Summer is getting close.I can feel the heat a coming.If someone can take the time to ponder this system, I would sure appreciate it.If I need to discharge the system, I'll have to take it to someone to do this.I would like to know exactly what is wrong before I take on this expense.Dont really want to do this more than once if I can help it.Thanks,Roger Sisler.
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TJ Hannink
Goldibox - 1987 Vanagon Camper, Wolfsburg Edition
1981 Bluebird Wanderlodge, FC-33
Winter Park, Florida
http://home.earthlink.net/~tjhannink/
http://groups.yahoo.com/group/wolfsburg_campers
http://groups.yahoo.com/group/FC_wanderlodge
FAVOR website: http://home.earthlink.net/~clubvanagon
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