I was wondering of what your opinion is on the following: I air the motorhome up level and put the HWH off not sleep. It takes about 5 day and the air is down to about 65lbs. However, the small pump that works off a small aux tank will start to pump filling the small tank, when I turn it on. I have a manual on-off switch to control the pump. The pump only runs for about 20 seconds. Any thoughts on where the air is leaking from the small tank. By the way, if coach main tanks are 70lbs or higher this doesn't happen ever.
Two things make the HWH compressor come on assuming power is available ...
1) the pressure switch falls below its minimum setting.
2) the HWH computer tells the pump to come on if air is required for raising one side or the other or one end or the other.
#2 happens in manual mode (in my coach) if you push a button to raise either side or end no matter what the pressure.
Look at your air system diagram. Depending on check valves and pressure protection valves the leveling manifolds could get air from the service tanks. The HWH compressor (normally) does not supply air to them. This air may be sufficient to help with leveling but the min pressure for levelling is about 90 psi. Not all coaches are the same. 2001 U320 have 3 different diagrams in one year.
Look at your wiring diagrams carefully, just interrupting power to the compressor does not interrupt power to the control side of things. The pump might not run but the switch says run and the water trap exhaust solenoid is powered. It gets very hot.
Interrupt power going to the essex relay may be better. Lots of different ways this was wired up over the years. Check your coach for the way it is connected.
Roger when the remote switch was installed it was attached to two leads that could cause the pump to go on one was as if the fuse was removed, and another was somewhere else that I can not recall. I was told that with the switch off the entire auxiliary system was shut down. Thanks for the input. Elliot
If you are adding in a switch in a power circuit consider using a relay to open or close the circuit. A much lower power loop (smaller wire) to the switch can actuate the relay.