Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: jimmy_walther on June 03, 2023, 09:14:38 pm

Title: Help! Air Pump Problem
Post by: jimmy_walther on June 03, 2023, 09:14:38 pm
We recently purchased a 2003 U270 36' one slide unit from MOT.  I had the unit inspected by an ex-Foretravel employee who not only inspected it but test drove it.  Other than a few minor issues, the coach appeared to be in good condition.  We live in the Dallas area and have taken one small trip to Galveston.  The coach drove great and everything seemed to be working ok. 

Today, I went over to storage to load some gear and the coach adjusted the level and then the air pump went on.  This had happened before and I assumed that was normal.  Usually, the pump would run for a short period and then turn off.  Today, the pump would not shut off.  I let it run for approximately 15 minutes and it would not stop.  The pump was getting hot and I got worried.  I found a fuse in the wiring and pulled it, that sopped the pump. 

What should I do now?  I'm not a mechanic but I can handle basic things.

Thanks,
Jimmy
Title: Re: Help! Air Pump Problem
Post by: turbojack on June 03, 2023, 09:21:07 pm
Sounds like you have a good air leak. It could be a fitting leaking or a bladder that has a tear and leaking. Ones more familiar with your year will Chime in.
Title: Re: Help! Air Pump Problem
Post by: Michelle on June 03, 2023, 09:32:12 pm
Today, I went over to storage to load some gear and the coach adjusted the level and then the air pump went on.  This had happened before and I assumed that was normal.  Usually, the pump would run for a short period and then turn off.  Today, the pump would not shut off.  I let it run for approximately 15 minutes and it would not stop.  The pump was getting hot and I got worried.  I found a fuse in the wiring and pulled it, that sopped the pump. 

So, likely a leak, but first thing to check is if the N/O solenoid valve on the condensate bowl isn't closing when the aux compressor is running.  It's a common failure.  It's normally open but closes when the compressor runs.  If there's a crack in the bowl or there's debris on the seat, it will leak air and the compressor won't achieve pressure.  Since this bowl sees significant temperature shock (rapid cooling when then solenoid valve opens to blow off condensation), it's common to develop cracks in the bowl where the solenoid valve screws in. 

Also recently, someone found the o-ring for the bayonet mount of that bowl wasn't sealing.  Auxiliary Air Compressor only able to pump up to 60 PSI (https://www.foreforums.com/index.php?topic=46234.msg470665#msg470665)

It's in the aux compressor bay, looks like this:

Title: Re: Help! Air Pump Problem
Post by: jimmy_walther on June 03, 2023, 11:35:26 pm
Thanks, I'll go take a look tomorrow.
Title: Re: Help! Air Pump Problem
Post by: dbennett9 on June 04, 2023, 03:48:44 pm
Another possibility is a sticking pressure switch. I had this problem on our coach and have seen it many times in other applications. Sometimes the pressure switch will stick once and never be a problem again, and sometimes it is a sign the pressure switch is failing.
Title: Re: Help! Air Pump Problem
Post by: jimmy_walther on June 04, 2023, 10:14:07 pm
Thanks, how do I identify the pressure switch?
Title: Re: Help! Air Pump Problem
Post by: Joe Phebus on June 04, 2023, 11:18:42 pm
This is the replacement I used on my Thomas.    Should look like that.  Easy fix.  Also recommend you add a pressure gauge at the same time if replacing it.

Pressure Switch, DPST, 1/4" FNPS, Diaphragm 9013FHG2J27: Electrical Boxes:... (https://a.co/d/e0UJlHk)