How much Freon when system is empty

[PeterH-350LE]

Finally getting around to recharging my AC system. How much freon would i need if the system is empty?

[bkahler]

Peter, are you filling it with R12 or R134a?

The info I received for Peanut is 2 to 3 cans of R134a. I know you're supposed to use less R134a if you're changing from R12.

I'm sure this is probably just enough information to confuse the issue

[SpletKay06]

Im not sure on your exact vehicle but theres usally a sticker around the engine compartment that says the system capacity. Thats a good starting point then use system pressure to dial it in.

[bkahler]

The Airstream motorhomes generally don't have any information anywhere that details how to service the AC system. There are a lot of us in the same boat as Peter.

Kinda frustrating to say the least

[SpletKay06]

The I would start around 2 lbs and use the gauges from there just be careful not to overcharge the system

[PeterH-350LE]

Originally Posted by bkahler

Peter, are you filling it with R12 or R134a?

The info I received for Peanut is 2 to 3 cans of R134a. I know you're supposed to use less R134a if you're changing from R12.

I'm sure this is probably just enough information to confuse the issue

Thanks Brad, thats a start, since I had no idea. This is an R12 system that was rebuilt about 10 years ago. We'll see what happens

[drboyd]

I'm sure you know to pull a vacuum to get all the air and moisture out first. If there's a sight glass on the system, that will also help you correctly trim the charge.

[PeterH-350LE]

Originally Posted by drboyd

I'm sure you know to pull a vacuum to get all the air and moisture out first. If there's a sight glass on the system, that will also help you correctly trim the charge.

Thanks, yes of course. My buddy has a pro shop with the proper equipment and was just wondering how much these systems hold, since any references to these "modified" systems are generally not available

[ROBERT CROSS]

On a converted system evac & recharge using the proper POE,(Polyolester) oil.
Do NOT rely on the r12 sight glass to determine when system is full, the POE will appear as bubbles in the glass and it's very easy to overfill.

Bob

[GWallace]

Peter,

Attached is the original compressor label from the factory on my 77 Argosy. The system was supplied by Chevy on the P30 chassis with all GM components. The label shows 3.25 lbs of R12 refrigerant.



Last summer I decided to change out my system and use R134a as the refrigerant. This new system only requires 2 12oz (1.5 lbs) cans to fill it up. The new evaporator is about the same size as the original GM/Harrison evaporator, but the condenser is one of the newer design parallel flow condenser and is a 20"X15" condenser. The internal volume is less I think. I obtained the new system from Old Air Products in Ft Worth, TX. Looking back I would have probably been just as well off leaving the original evaporator and just replacing the hoses and condenser/dryer.

I also looked at the on line manuals for Claasic Auto Air and they suggest starting with 2 12oz cans with their R134a kits.

Gregg

[GWallace]

If your system is like my original system with 3.25 lbs of R12; but has been converted to R134a, then 20% less would be 2.6 lbs of R134a to fill the system.
I have discovered that R134a systems are more temperamental being overfilled than R12 systems especially as the ambient temperature rises. However a R134a system properly installed and filled really works well.

Gregg