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Topic: Auxiliary Air Pump frequently running (Read 979 times) previous topic - next topic

Auxiliary Air Pump frequently running

I've been chasing down air leaks for the last two months that I've had this new to me 09 Nimbus and yet my Aux pump cycles on and off all day.  It seems that when cold at night (Mid 30 degree) it runs every 7 min, and when warm durning the day (70 degree) it's 20 to 30 min.  The coach stays level with the leveling system off and the slide seals seem to be holding air - what else should I be looking for?
2009 Nimbus CE
2016 Jeep Cherokee Trailhawk
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Re: Auxiliary Air Pump frequently running

Reply #1 –
Have you checked for leaks on your slide bladders? Just had the living room slide bladder replaced because of a leak and now the bedroom slide bladder is leaking
The selected media item is not currently available.Keith & Jo
2003 U320T 4025 PBBS Designer series
Build 6203    Cummins 500hp
2000 U320 4010 WTFE / Build 5762 —Sold—
Motorcade #18070   
Pasadena, Texas
2015 Jeep Wrangler Sahara-Sunset Orange pearl coat
Don't argue with a fool, people watching might not be able to tell the difference.

Re: Auxiliary Air Pump frequently running

Reply #2 –
Quote from: hdff –
Have you checked for leaks on your slide bladders? Just had the living room slide bladder replaced because of a leak and now the bedroom slide bladder is leaking

I think it was Dan Weaver who observed that the slide bladders seem to have a lifespan of 7-10 years.  Just like tires, they are made of rubber and tend to age out.  If one goes for what appears to be age of that range rather than acute damage, it might be wise to have both/all done at the same time.

On a 2009 Nimbus, if these are original they are up to 12 years old.

Every 20-30 minutes could be attributed to the leveling system waking up - I believe 30 minutes is its interval.  Every 7 minutes definitely sounds more like the pressure in the slide bladder system is dropping fast.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

Lifetime Escapees' member SKP 82766
Former 1999 30IB Lazy Daze (2000-2004)
Former 2003 U320 (2004-2016)
Former 2017 LTV Unity (2017-2023)
Shopping for our next coach

Re: Auxiliary Air Pump frequently running

Reply #3 –
Quote from: hdff –
Have you checked for leaks on your slide bladders? Just had the living room slide bladder replaced because of a leak and now the bedroom slide bladder is leaking
I'll get up on a ladder today and check them all.
2009 Nimbus CE
2016 Jeep Cherokee Trailhawk
 ̷2̷0̷0̷6̷ ̷C̷o̷u̷n̷t̷r̷y̷ ̷C̷o̷a̷c̷h̷ ̷I̷n̷s̷p̷i̷r̷e̷

Re: Auxiliary Air Pump frequently running

Reply #4 –
You can turn off the valves that supply the air to the slide out air manifolds to see if that stops the frequent cycling.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Auxiliary Air Pump frequently running

Reply #5 –
Quote from: red tractor –
You can turn off the valves that supply the air to the slide out air manifolds to see if that stops the frequent cycling.
Are those located in the same bay as the Aux pump?
2009 Nimbus CE
2016 Jeep Cherokee Trailhawk
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Re: Auxiliary Air Pump frequently running

Reply #7 –
Quote from: AC7880 –
On a 2003 U320 they are.

And they look like this in a 2003, except instead of red-handled 1/4 turn brass valves (see above the solenoids), the original valves have black plastic handles.  On the 1/4 turn valves, parallel to plumbing is open, perpendicular is closed.

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Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

Lifetime Escapees' member SKP 82766
Former 1999 30IB Lazy Daze (2000-2004)
Former 2003 U320 (2004-2016)
Former 2017 LTV Unity (2017-2023)
Shopping for our next coach

Re: Auxiliary Air Pump frequently running

Reply #8 –
If you have an older coach than the 03 or 02 with these valves OEM they are not hard to add to yours. I did it in my 2001. The valve isolates the slide seal. Add a pressure gauge as well, your slide seal should have about 12 psi (some variation perhaps) and hold pressure. 

The valve and pressure gauge will help isolate problems. If the slide seal is leaking and you close the valve then with no other leaks the compressor should stop running.  If you close the valve and the compressor keeps cycling you have a leak elsewhere.  If you close the valve and the slide seal holds air then it is not leaking.  If you close the valve and the slide seal does not hold air then the slide seal is leaking.  If the valve is open and the seal does not hold air the slide seal is likely leaking but if could be the slide seal manifold or any air connection.

Air leaks are never simple and as soon as you fix one another is likely to follow. 

Roger

Re: Auxiliary Air Pump frequently running

Reply #9 –
What I did is pulled the inline fuse to stop the pump and the coach stays level and the seals are inflated.  Is there a pressure sensor that could be faulty?
2009 Nimbus CE
2016 Jeep Cherokee Trailhawk
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Re: Auxiliary Air Pump frequently running

Reply #10 –
The pressure switch, usually has a gray cover, can go bad or stick open or closed.  Mine would stick open and not come on sometimes.

The water separator on your setup has a solenoid valve on the bottom that closes when the pump runs and opens when it shuts off. These can fail as can the plastic bowl of the water trap.

Michelle's note next is correct about the water separator.  Probably not the problem but check it anyway.

You probably have a switch on the side panel for "air", not sure what it says.  It should be off. When on it opens a solenoid valve that sends air to the wet tank.  If you are trying to isolate leaks start with that off.

Re: Auxiliary Air Pump frequently running

Reply #11 –
Quote from: Roger & Susan in Home2 –
The water separator on your setup has a solenoid valve on the bottom that closes when the pump runs and opens when it shuts off. These can fail as can the plastic bowl of the water trap.

When this solenoid or bowl fails/develops a leak, the aux compressor never stops running because it can't build pressure while operating.  The solenoid valve on the bottom of the bowl is a NO one, so if the compressor is not running, that valve (and the bowl) is open to atmosphere.  Since the compressor does shut off, I would not suspect this bowl.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

Lifetime Escapees' member SKP 82766
Former 1999 30IB Lazy Daze (2000-2004)
Former 2003 U320 (2004-2016)
Former 2017 LTV Unity (2017-2023)
Shopping for our next coach

Re: Auxiliary Air Pump frequently running

Reply #12 –
RE: this statement from above- "The water separator on your setup has a solenoid valve on the bottom that closes when the pump runs and opens when it shuts off. These can fail as can the plastic bowl of the water trap."-....

a couple of weeks ago I was having same problem with  compressor on my U270 not shutting off and it turned out to be the plastic bowl had cracks at tits radius base. With compressor running, I could feel the air escaping by putting my fingers around base of bowl  in area where the solenoid connects to it. I ordered replacement bowl from Foretravel parts, and once installed, problem was solved.


2014 Honda CRV
Washington, Vermont
Lady Lake, Fl,  Independence, VA
Former owner of 2002 U320, 2003 U320, 2005 U270

Re: Auxiliary Air Pump frequently running

Reply #13 –
The 12 volt compressor was running constantly which in my mind meant there had to be a substantial leak and should have been easy to locate.  After isolating the slides, coach remaining level and soaping down the lines replaced the pressure switch, problem solved.
Gary Mauck
Deerfield Beach, Fl.
2005 U320 40' PBGB

"Elks Care, Elks Share!"

Re: Auxiliary Air Pump frequently running

Reply #14 –
Quote from: cdm –


a couple of weeks ago I was having same problem with  compressor on my U270 not shutting off and it turned out to be the plastic bowl had cracks

Exactly as I described above - if the pump won't turn off this might be a culprit.  However in this case the OP states the compressor shuts off just fine, it just starts back up again after 7 or so minutes at night or 20-30 in the day.

This is not a symptom of the condensate bowl, which is always open to atmosphere unless the compressor is running.  The compressor will not turn back on just because the bowl is cracked IF it has already met pressure.  If the compressor can achieve pressure and shut off, as it does in this case, something else is leaking.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

Lifetime Escapees' member SKP 82766
Former 1999 30IB Lazy Daze (2000-2004)
Former 2003 U320 (2004-2016)
Former 2017 LTV Unity (2017-2023)
Shopping for our next coach

Re: Auxiliary Air Pump frequently running

Reply #15 –
Quote from: Michelle –
And they look like this in a 2003, except instead of red-handled 1/4 turn brass valves (see above the solenoids), the original valves have black plastic handles.  On the 1/4 turn valves, parallel to plumbing is open, perpendicular is closed.

 The selected media item is not currently available.
I found my leak!!!  I put the fuse back in the pump and let it fill the system up.  While in the bay I heard air leaking when the compressor shut off.  I sprayed around with my bubble mixture ant  it's that shut off valve in your photo - except mine seems to be made of black plastic and is leaking at the lever itself.  Now to find one - do you recommend Foretravel or HWH?
2009 Nimbus CE
2016 Jeep Cherokee Trailhawk
 ̷2̷0̷0̷6̷ ̷C̷o̷u̷n̷t̷r̷y̷ ̷C̷o̷a̷c̷h̷ ̷I̷n̷s̷p̷i̷r̷e̷

Re: Auxiliary Air Pump frequently running

Reply #17 –
Quote from: MarkC –
You should be able to use a standard ball valve like Roger detailed. Something like this will work.
1/4 Inch Ball Valve NPT Air Compressor Brass Valve Female Male Shut Off...
Perfect!  Thanks so much
2009 Nimbus CE
2016 Jeep Cherokee Trailhawk
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Re: Auxiliary Air Pump frequently running

Reply #18 –
See Michelle's picture in Reply #7.  Ball valves work great.
Mark & Bev
2001 U295 36'
Cummins ISC 8.3 350HP
Build #5802
Jeep Wrangler Toad