AC Question
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Joined: Jan 2001
Posts: 83
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From: Snellville, GA, USA
AC Question
All,
I have a 69 coupe that Im trying to get the AC to function correctly. I have replaced the condenser, expansion valve, evaporator & belt. I had the thing vacuumed & charged. The service person told me that the VIR valve is freezing and needs to be replaced to allow proper flow. (the car has been converted to latest freon) He also said that the compressor wasnt cycling and that the switch was bad. He didnt know where it was. Can anybody tell me about these two items? What the VIR does and where the switch might be located?
thanks in advance
Steve
I have a 69 coupe that Im trying to get the AC to function correctly. I have replaced the condenser, expansion valve, evaporator & belt. I had the thing vacuumed & charged. The service person told me that the VIR valve is freezing and needs to be replaced to allow proper flow. (the car has been converted to latest freon) He also said that the compressor wasnt cycling and that the switch was bad. He didnt know where it was. Can anybody tell me about these two items? What the VIR does and where the switch might be located?
thanks in advance
Steve
Burning Brakes
Joined: Feb 2004
Posts: 958
Likes: 1
From: In the Beautiful Shenandoah Valley of VA
You might want to try another mechanic. VIR is the anachronym (sp?) for "valves in receiver". VIR is a system that places the thermostatic expansion valve (TXV) and the POA valve (forgot what that one stands for - pressure something accumulator?) into one receptacle next to the evaporator; you can see the dessicant "can" hanging down under the piping and VIR assembly under the passenger fender. VIR doesn't use a cycling switch, the two valves inside the assembly work in conjunction with each other to control the evaporator pressure to around 28 to 34 psi. Cycling systems (known as CCOT) arrived around 1976 for better fuel economy and lower weight.
I'm pretty sure that a '69 didn't have a VIR setup (someone will correct me if I'm wrong), but instead had a separate external TXV and POA valve (sometimes known as a suction throttling valve). I haven't dealt with an R-134a changeover on either system yet, so I can't tell you exactly what might be wrong, however, a search through the archives might help.
Anyone?
Steve
I'm pretty sure that a '69 didn't have a VIR setup (someone will correct me if I'm wrong), but instead had a separate external TXV and POA valve (sometimes known as a suction throttling valve). I haven't dealt with an R-134a changeover on either system yet, so I can't tell you exactly what might be wrong, however, a search through the archives might help.
Anyone?
Steve
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Stave about covered it, the mechanic most likely dooesn't see these older cars very often, so got forgetful between POA, which does fail and costs about 50 bux through NAPA...and the VIR system, which followed our system for about 2-3 years there....in the mid 70's....which Steve covered above....
Zwede here says to turn the nut on the exit end of the new POA valve about 1/4 turn counterclockwise for best performance with R134....
other than that, just fill with 75% or so of the recommended amount of freon...my system took about 2.5-3 12 oz bottles...
there is no pressure cycling switch....our systems are far superior to that, pressure cycling is just a cheap way to do things....
GENE
Zwede here says to turn the nut on the exit end of the new POA valve about 1/4 turn counterclockwise for best performance with R134....
other than that, just fill with 75% or so of the recommended amount of freon...my system took about 2.5-3 12 oz bottles...
there is no pressure cycling switch....our systems are far superior to that, pressure cycling is just a cheap way to do things....
GENE
