Re: AC

[Dave Head <dhead@sundial.sundial.net>]

>At 07:14 PM 4/25/96 -0500, you wrote:
>>
>>Regarding removing the existing refrigerant and trapped air:
>>
>>I was at the repair shop today and the coolant was down 1.5 lbs (1lb
>>remaining). They added 1.5 lbs and were unable to find any leaks. Is the
>>refrigerant under pressure or does air come in when the refrigerant leaks out?
>>
>>michael
>>
>Michael, 
>  Yes the refrigerant is under pressure.  Anywhere from about 60 psi on the
>low side to about 300 or so psi on the high side. Can't remember exact
>numbers right off hand.  Air will only enter the system if there is enough
>of a leak where the pressure in the system bleeds off to atmosphere.  There
>are a couple of reasons to make sure the air is evacuated from the system
>before recharging with freon.
>These are the ones I know of and there may be more.
>
>1. Air does not respond the same way as freon when it goes through the
>system      thus reducing the efficiency.
>
>2. Air usually means moisture which is very bad in an air cond. system.
>Moisture can freeze in the orifice in the evaporator coil and clog the
>system.  It can also cause rust in the a/c system.  This is why it is a good
>idea to replace the receiver/drier when the system has been open.
>
>On the 5k's the schrader valves are hidden under switches, so they are not
>obvious like on other cars I have worked on. Don't know about other Audis
>however.
>
I had my system gone through 3 months ago - added 1.5 pounds, no leaks. Over
the last month the AC has gotten worse and worse - then the clutch started
cycling on low pressure (as it was before the first recharge). Started
checking - Yep- Leaking Schrader valve!  If this is your problem, its hard
for them to find, because thats what the hoses are hooked up to when they
are checking for leaks.
********************************AUDI FAN******************************
EMCM(SW) Dave Head (nuclear grade electrician)
87 5KCSTQ 170K miles and not counting (damned VDO odometers)...
1.9 bar boost (charlie spring, no shim) - @ 1.3 the shuttle launches!
Maitland FL
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