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Thomas on-board Compressor?

Yahoo Message Number: 91586
I changed out the 1/4" plastic air line over the compressor, to a copper line today., I had a small leak there where the line had over heated, had cut it off a couple of times, but now the compressor will not come on as usual when leveling, I noticed that it had tripped the fuse(breaker) in the rear battery compartment. I reset the breaker and tried again, with the same results. Any one have an opinion? I also cleaned the glass bowl while I was there, What did I do to cause this problem?, or was it just about ready to kick the bucket anyway...
Marvin, 07 Allure, 470, 31459

Re: Thomas on-board Compressor?

Reply #1 –
Yahoo Message Number: 91639
Marvin - That compressor includes an unloader solenoid to relieve pressure against the piston when it starts. Unlikely this is the problem but worth checking. The other obvious inspections would be for short circuits in the power feed wiring. You could remove the power feed line from the compressor and jumper some power momentarily into the compressor motor using jumper cables. See if the motor twitches and attempts to start. A wiring short would pop the breaker immediately.
So this sound like something relating to the motor and/or starting torque. Perhaps the compressor motor and/or piston is seized for some reason. You can remove the feed line to ensure the compressor is starting with no back pressure. That assumes the check valve plate is functioning properly. It may also be a weak DC breaker. The breakers in my battery box look pretty cheap. Last I checked that compressor was around $750. Not sure about breakers which don't look easy to get at and/or replace.

I did the copper tube thing about 5 years ago. Link is here: http://www.muniac.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=146#Post146 I made a simple inter-cooler as well. Good luck.

Best - Scott

2006 Allure 430 40' #31349

(Bus-Stead Lemon) My Allure Page http://www.muniac.com/Allure%20Page.html

Re: Thomas on-board Compressor?

Reply #2 –
Yahoo Message Number: 91642
Scott Thanks,

I did remove the compressor and connected it directly to 12v, jumper and it ran as usual, I don't think it is a problem in the Compressor. I re-installed it and have not thought too much more about it, I do not have a loss of air so I was just waiting to run the air pressure down to where the pump will start, or suppose to start.
I was thinking that it may be too much head pressure, do you know where the solenoid is located? I might add, when I removed the air line from the compressor it was fully charged with air, I put it back on and dumped all the air out of the system. The relay on the pump seemed to work fine with 12v touched to it. My compressor is located in the front compartment under the driver, there is a valve there that has other lines attached. Thanks for the response.
Marvin, 07 Allure, 470, w/tag

Re: Thomas on-board Compressor?

Reply #3 –
Yahoo Message Number: 91647
Marvin - I've got the Parker clear glass bowl filter. Probably pretty common. The compressor motor relay is mounted to the back and the small unloader solenoid valve is on the bottom of the glass bowl. I gather the valve is normally open. When the compressor starts, that valve closes. When the cycle is completed (power goes away) the valve opens and relieves the pressure on the system. This ensures the compressor doesn't start against any back pressure. It's a pretty simple and common system found on most air compressor setups. It's good you don't have to pitch out for a new compressor.

There is a level sensing board in the HWH system. At times in winds the bus will rock a little bit. Water in the storage tank can slosh around too. That can short cycle the compressor as it's fooled into thinking leveling is required. Just when it starts water or wind changes satisfying the level board sensor. The effect is the compressor comes on then goes off then comes on again then goes off. Perhaps in 10-15 seconds. Should the unloader valve be sticky or not working I could see this popping a breaker. Good luck.

Best - Scott

2006 Allure 430 40' #31349

(Bus-Stead Lemon) My Allure Page http://www.muniac.com/Allure%20Page.html

Re: Thomas on-board Compressor?

Reply #4 –
Yahoo Message Number: 91668
On my 2006 Inspire, the aux compressor stopped working when leveling. I could level if I left the engine running long enough. The fuse was blown, replaced the fuse and it immediately blew the fuse again. So I got the Thomas part number and bought a new compressor from Zoro tools on the internet for about $250. Two wires and three bolts and it was replaced, about 20 minutes. Works fine now.

Orlan Larson
2006 Inspire, 51701