Hi,

First let me say, I`m a new member and have been reading posts for a few weeks now. I`m very impressed at the wealth of Knowledge and how everyone generously shares it!!!

I am presently trying to get the A/C system in my `74 350c.i. L82 figured out, I have replaced the condenser, VIR Assembly, All "O"rings, Flushed the system,cleaned out the evaporator box as best I could(Pulled out 4 handfulls of leaves)and blew it out with compressed air too, Vacuumed it down for an hour and a half, Pressure checked it with nitrogen at 90psi. Then serviced it with Freeze12. The pressures are right-on per the freeze12 website and have seen vent temps of 55 degrees on Max cool. The Lines out of the compressor and Evaporator are Nice and cold also.

Now here is my main concern, the low pressure cutoff switch does not cycle the A6 compressor when the low side gets to 25 psi or so...I know the switch works, since the clutch didnt get energized with No Freon. But isnt it supposed to kick off the compressor to prevent freezing?

Is the A6 in a `74 VIR AC System a "Constant Duty" Compressor?
What is the Cutoff switch rated At, As far as Low pressures are concerned?
Is there some sort of adjstment somewhere else since the Cutoff switch has none?

Hopefully I have given enough Info for the AC Guru`s out there!! and thanks in advance for any help.

-la-

 

Yes, on a VIR system, the compressor runs all the time. I have the same system on my 73. You can buy a VIR eliminator kit for about 150 bucks that lets you convert the system to a more modern system that cycles on and off.

Eddie

 

Thanks for the prompt reply!!

What vent temps are you seeing on max cool? Also what freon are you using?
Isnt evaporator freezing a problem with this kind of a setup?

-la-

 

If you are only getting 55 degree vent temps, you have little to fear about the evaporator freezing. You'd be seeing 35 degree vent temps when that heappened.