I've wondered about that as well. Haven't found anything but general info. about it. Pretty much add 1 oz. per major component replaced. I.E. compressor, condenser, evaporator, dryer. But I am certainly no authority. The moderators on this forum will know.

Ambient temp was 85-90 F

Didn't notice any sounds from the compressor but this is a diesel pusher MH so I was at one end and the compressor at the other. I have not seen any residue or dye either as I also had that in the system. I wondered if there was a pressure relief valve. Makes sense. Thanks again.

Thanks for the help. The fan was the problem. My gauges now read 35 low and 225 high and I have cold air. It just happened to fail while I was in the process of replacing the pressure switch and THX, and I had tunnel vision and wasn't looking for additional problems. Looking back on it I do remember...

I appreciate your response JohnHere. Yes this is a 134a system built on a Freightliner chassis. No underhood sticker, but Freightliner said it is a 2.8 lb. capacity system. I only put 38 ozs. in because the pressures were climbing alarmingly high quickly, so I stopped. Yes, it held a 29 Hg vacuum fo...

That's my question. Is it possible they are giving me the wrong valve? If so would that cause the problem I'm having? Are they made for different pressures or other paramaters? All I know is they look the same. My original has numbers on it, but the new ones do not other than the part numbers on the...

I'll say up front I'm not an experienced A/C guy, but I'm learning. I have an RV that the dash A/C was working when charged with Freon, but had a Freon leak and would leak down pretty quickly. I finally found the leak which was the pressure switch. This was complicated by the fact that the pressure ...