What is the refrigerant capacity for a rear HVAC van with R134a?

[Jeff H WV]

The pressure hardline for my rear unit rusted out and I had a new hose made to replace it. I am going to convert from R12 to R134a, as my system is empty. Would be nice to eliminate guesswork as to how much to charge system. I wouldn't think difference in condenser would make alot of difference. Thanks, Jeff

 

[BrooklynBay]

A/C freon & oil capacity chart for the Aerostar.

This is one of the links in # 13 in my list of useful threads: http://www.explorerforum.com/forums//showthread.php?t=315415

 

[scdix50]

Haynes make a great techbook A/C. Be aware that R134a gages are different than the old R12 gage set If you are using one of convertion kits, IT should tell you which oil to use with your system. You have not changed your volume of the system, so plan on having enough R134a to meet that volume. Your lower pressure switch is set at 20psi. Pull your vacuum, hold to check for leaks. Add your oil, then R134a, Watch you lower pressure gage, If you have trouble getting the pressure over 20psi to start you can set your cans in hot tap water. NOT BOILING WATER! At this point your compressor should start cycling on & off. Just keep adding until you 10-15psi above the off/on cycle. Your spec. is 20 to 50 low side and 160 to 250 high side. I stop there and drive it around a day or two. If your not happy with the temp go back and add some more. Keep in mine that the hotter the days-the higher system pressure. R134a just does not cool as good as R12. Please be careful, good luck

 

[Jeff H WV]

Thanks for the responses. I pulled vacuum this afternoon and so far it looks like it's tight. I'm going to charge it tomorrow if it holds. I had a hose made with a compression fitting on it to mate to the hardline going to the front and I don't entirely trust them not to leak even though I've had one on the condenser on my truck for over two years and it hasn't lost any yet. I always heard that you had to use less R134a than what it called for R12. Knowing the pressure readings will take away the guesswork. Thanks again, Jeff