How much freon in Dash AC?

[Max]

Hello to everybody,

its time to fix the dash ac in my rig. I replaced the Tecumseh compressor by a York210 style, installed a new dryer and expansion valve and cleaned the pipes, condenser and vaporizer with breakcleaner and compressed air. But i cant find any information about how much freon belongs in this system. Its an r12 system and i am planning to replace it with r12a. If i know, how much r12 belongs in it the ac shop should be able to figure out the amount of another refrigerant.
Thanks in advance for any help

[eXodus]

"The system holds 3.25 lb of R12 in case anyone else out there ever needs to know or cares... Took me five days to get the answer, searched online for hours and hours, asked everyone I thought might know and finally got a number from a reliable source, a source I'll never reveal"

https://www.airforums.com/forums/f311/1987-p30-r12-freon-capacity-76528.html

But any reputable A/C shop should be able to charge according to pressures and temperatures without knowing how much exactly goes into a system.
It takes a while - since you basically have to add half LBS freon - let the engine run for 10 minutes for while running the A/c and then check pressures.

You need 4 temperatures in A/C system:
- incoming Air before the evaporator
- exhaust air (cold air)
- coolant line before the compressor
- coolant line after the condenser

+ Ambient Air
The both high side and low side pressure.

Plug all those values in a table and you get an answer how much you still need to charge.
(studying for my EPA certification ATM)

[Max]

Great, thank you very much. Thats a number we can work with. Here in Germany no one knows this old RVs and if there is no OBD connector they are mostly helpless.

[eXodus]

Viele Grüße nach Deutschland von Florida.

there are a few Germans on this forum. We Guys should start a Winnebago Stammtisch.

[Max]

That is a good idea with the Stammtisch.