Need assistance ASAP

Also, how much freon does an empty system require?
Will

quote:

Originally posted by 4NHOTROD:
Also, how much freon does an empty system require?
Will

I converted my car to a Sanden rotary compressor and R134 with a thicker condenser than stock, but still in the same location. It took about 3.5 to 4.0 lbs to fill the system. My 1973L stock system did not have a pressure switch on either the low side or the high side, although I intend to install at least a low pressure switch when I move the condenser to the front of the car. As I recall, you can run the compressor from the switch in the car even if the system has no Freon.

Sounds like a shop will be charging the system. If they are good they know how to eliminate the guess work in the amount of freon required.

Too much is as bad a too little when it comes to R-134. I assume the same for R-12.

Some shops start with a baseline charge for the system (like 3 pounds), then run it. They measure the cold air temp output. Add a little more and see the effect. If it drops, add a little more until it maxes out. If they add too much, the temps no longer drops. Might even increase. Trial and error, but gets it to the best setting for that specific system.

We learned this system for Big Rig Truck AC systems. Too many variables with hose length and general system condition. So a little fine tuning was always require to keep the drivers happy.

quote:

So a little fine tuning was always require to keep the drivers happy.

Agreed, every system is a bit different, and adding an ounce at a time after basic charge will find the lowest temp.

But were you concerned with high/low pressures at all?

Larry

You do need to watch the guages while you are adding freon. External factors like the temp and humidity will also effect the charging process. So watching the guages is needed to assure one does not over or under fill the system.