[Chester Stone]

Richard, in my post #13, I questioned if there was an override to the pressure switch. I would be helpful if you posted a photo of this override wire location of some identification of it. I may disconnect it or install an on/off switch. I normally level my coach using the engine compressor in high idle and leave the HWH level switch on to keep the coach level over time. Perhaps I am wrong, but I see no need for the override since the 110 compressor should provide enough air, it may just take a little longer. Why not put our trust in the air pressure switch? What am I missing?

[Richard]

Chester, Look in the blower bay. You will see two boxes bolted to the floor. One of them has an air line going into it. That is NOT the over ride. If you take the top of of the other one, you should be able to differentiate between the 110 V power wires and the wires going into the coil. The the 110 wires will be terminated at the contacts.

I read your leveling strategy carefully. Here is the fly in the ointment. On my coach, and yours is similar. It really takes about 80 psi just to float the coach on the airbags. If you disconnect the override, I am not sure the aux compressor limited to 90 psi would level the coach.

Since the thomas pump is capable of system pressures higher than the 120 psi that the coach normally sees, I will probably install a regulator downstream of the pump when I get home.

[bikestuff]

What is this "aux compressor" that you speak of? I understand the engine air compressor, and the Thomas / Gast but what is the aux?

Richard, A little clarification? Lets say that you are in a position whereby there is no chance of ever getting level. Like that driveway that you blew up your bag. You go into auto-level mode and the HWH tries to do its thing. Once the bag is full it keeps putting air in trying to raise the low side. Is that when the bag blew up?

On my system, it let air out of the high side, but doesn't ever seem to want to add air to the low side. (I can do it manually, but in auto mode not so much).

Can you add a few more words about this situation?

Thanks!

[Chester Stone]

My coach has the Jun-Air 110 volt compressor located in the generator compartment. It seldom runs and is exceedingly quiet. It shuts off at 105 lbs. Attached are two photos showing the air pressure switch, with and without the cover. Nothing is bolted to the floor. I note that there are two sets of wires going to the two terminals in the air pressure switch. Obviously, one is the 110 volt source from the on/off switch located in the galley. The other set comes from the wiring harness with no coil in sight, and may be the bypass for the HWH system. I am hesitant to disconnect them know knowing exactly what their function is. Wonder if anyone has the wiring schematic for the HWH system.
       

[RussWhite]

I find this a very interesting thread. It explains a number of things I had not fully understood.
I was aware there were two devices that would run the auxiliary compressor and knew that the "well pump" switch was the one that ran the compressor in my case. I had no idea why there was another contactor and could not even speculate on a reason it would be necessary. I just figured it would remain a mystery.
Subsequent to that I had the coach connected to a shop's air compressor system and when fullly aired up, the shop air was showing around 130psi on my gauges. That is a bit higher than the cutoff on my engine compressor, but not dramatically so. Well, when the shop air was on there was an audible leak in the right front bay. The leak would stop as soon as the air was removed. I was not able to isolate the leak at the time I was in the shop. When I returned home I noticed the auxiliary compressor running more than normal and went on the prowl for the reason. My ultra-sonic detector quickly located the leak at what appeared to be an pressure regulator with nothing connected to its output. This device was located right at the "well pressure" switch.
I contacted Newell and was informed this was a pressure relief valve and was used on some coaches, but if it was leaking and I wanted to remove it to go ahead. I figured that once it had been necessary to relieve pressure it was unable to seat perfectly again and would continue to leak at even normal pressures. So I removed it.
Now I know why it was there if the mystery contractor is activated by the HWH leveling system and runs without the benefit of any pressure switch to limit the pressure produced. I am undecided right now what I will do. I never leave the leveling system on after I am level and I doubt my little dental auxiliary compressor could reach pressure sufficient to damage anything, but I sure see how it might happen.
I will most likely just disable the HWH contactor to be safe.
I have attached a picture of the relief valve I took prior to removing it.

[Richard]

Sorry for confusing terminology. The auxiliary compressor is one and the same with the Thomas/gast/junair.

Chester that is the well pump switch in your pics. Don't disconnect any of those wires. I will post a picture of my setup tomorrow when it's light enough to take a picture.

[Richard]

If I get this right, the first pic shows both contactors. The second, a larger pic of the override contactor. The third, is the innards of the override contactor. I can't tell the color of the trigger wire.

Russ nailed it. I too have the pressure regulator on that line, so that is the protection mechanism to prevent high pressure from the aux pump. However I have no idea where it is set to relieve pressure. I'll have to put a guage on it and see

[bestgenman]

Richard & Russ, you guys have nailed the comment I made about the 120V running without the protection of the pressure switch (aka well pump switch) while the HWH is in level mode and needing air.

Newell is using a pressure regulator ( the regulator without any connection to the output) as opposed to a "pop off" relief. I'm not sure how this regulator works as a pressure relief device just yet since the device is normally open until the set point is met. I believe it is designed to work as a pressure relief device (normally closed until set point is reached) and different from the other regulators in use on our coaches.

Anybody have insight to this device?

[lbrachfe]

It was cold two nights ago and my compressor started acting up. It sometimes works normally for a cycle and then a ghost in the high pressure relief valve then evacuates the air I just put in. I warmed the bay and got it working normally , but after a few hours compressor would not come on. to stop the air evacuation from the release valve I separated the housing pieces and them put them together again and the valve close, but then the compressor tries to turn on for a moment and then nothing. The 12volt works fine and kicks in at 30lbs. I don't have any leaks as the air hold pressure for more than two hours and that includes using the door , toilets, etc. I just put in a new check valve and HPR valve 3 months ago. Any ideas for me when I take it all apart ???? Could the 1/2" check valve go bad ? I replaced a 1/4" one and all has been ok until some cold weather which was only at night.... I don't know where to start, except pulling it all apart. Any Help from Richard or Steve or Tom since you 3 write great explanations to stuff...

[Richard]

Thomas compressor?

If you just take all the air line components loose from the compressor will it run? If not, is it getting power? Sounds like the cold weather iced up the water in your system.

If it runs then I would take a careful look at both the check valve and the relief valve to see if they are iced up or damaged when they iced up.

If it doesn't run, but you have power, try to turn the compressor by sticking a screwdriver in the fan opening and twirling the fan. Is the compressor seized? If it is, then loosen the 8 screws that hold the top on the Thomas compressor. Loosening the screws will relieve any pressure internal to the compressor. After loosening the screws will it turn? Will it run?

If it doesn't have power, I would check my well pump switch in the generator bay to see if it iced up.

Call me if you want to chat 817 223 2056.

Richard in balmy West Virginia. Brrrrrrrrrrrrrrrr.