Ductape wrote:
Nonsense. Mine does not leak. Any tech worth his pay can find and fix the leak in the a/c.
Ductape is correct, they do not leak inherently leak.
Back in the days when I was a newby, I had the same problem with the A/C on a P32 chassis mounted MoHo. I spent a bit of money on a RV repair shop "fixing it" with absolutely no luck.
I was doing one of my infamous sit and ponder things when I decided to look into the vacuum system. Without doing a tedious step by step test description, I started with the source and tested every hose and actuator and selector switch in the HVAC's vacuum system.
I have a MiteVac hand held vacuum pump. I finally found a actuator(motor) for a door that opened and closed the inside/outside air had a hose from the plastic vacuum tube to the actuator that sorta, kinda. almost maybe fit the tube from the actuator. In other words, I found that the installer used the wrong size hose in a very inaccessible place that neither fit the plastic supply line nor the actuator.
Replaced the hose and, no more leak and therefore, no default to defrost when climbing long grades.
On most systems there is HVAC panel that usually has about 6 or 8 vacuum hoses attached to it. One hose, usually the largest, is from the reservoir and the rest are to the actuators. Vacuum test each line to and from the reservoir and the actuators until you find one that won't hold a vacuum.
When I called the shop that "fixed it", and told them that what took them a couple of weeks to fail at, I found and fixed in about three hours. I asked for the money backed that they charged for "fixing" my system because my troubleshooting durned up absolutely no evidence of any testing or repairs. There was dirt and dust on parts they suggested they had removed or replaced and tested. and finally when I told them to forget it, I would just let a Small Claims Administrative Judge decide, they returned my money. When I told the owner that I would be happy to come to his shop and without charging him a cent, teach his HVAC guy how to trouble shoot a problem like mine, he told me in some very vulgar terms to never darken his doorstep again.
