From: ghg@cidmac.ecn.purdue.edu (George Goble)
Newsgroups: rec.autos.tech
Subject: Re: Any AC techs?
Date: 11 Apr 1995 14:27:05 GMT
Message-ID: <3me3jp$gpp@mozo.cc.purdue.edu>

In article <24.47258.2645@pcohio.com> danny.fitzsimon@pcohio.com (Danny
Fitzsimon) writes:

 >Anyone knowlegeable in charging auto AC systems care to review my 
 >charging procedure, add advice, comments?
 >
 >This is an '85 Toyota Corolla that I've just fixed 4 small leaks on.
 >System has been vacuumed(by me) and is now ready to go. Only thing is
 >I'm getting conflicting opinions on the procedure for charging.
 >
 >Anyway, how about this concensus?
 >
 >Hook up gauges and liquid charge thru the low side w/engine off. Turn
 >AC gauges off. Then procede to turn engine on, warm up and continue
 >with liquid charging till recomended wt. of freon is in. 
 >
 >Thats about it, right?
 >
 >Forgot to mention that I do have a digital scale that measures to the
 >1/2 oz. The system takes a whopping 24 oz. total. 

 
Liquid into high side with engine off.. this reduces two problems.

1) If there is lots of liquid in the low side, esp near the
compressor, upon startup, one can "slug" the compressor
and maybe bust the valves, trying to compress liquid.

2) Newly entered liquid on the low side, may "wash away"
lubricating oil on startup, causing the compressor to run
for a few mins with little or no lubrication, until the
refrigerant and oil mix. Charging on the high side, causes
oil to be returned to the compressor on the first trip
thru the circuit.

Don't charge on the hiside after starting the engine though.
Charge into the low side then.. barely crack open the
manifold valve (if charging liquid), so it boils off
in the hose and doesnt slug the compressor.

--ghg  (inventor of R-406A)