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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...

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  • hdff
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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

Re: Auxiliary Air Pump frequently running
Reply #2
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...

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Re: Auxiliary Air Pump frequently running
Reply #3
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...

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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.

Re: Auxiliary Air Pump frequently running
Reply #5
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?


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  • AC7880
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Re: Auxiliary Air Pump frequently running
Reply #6
Are those located in the same bay as the Aux pump?

On a 2003 U320 they are.

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Re: Auxiliary Air Pump frequently running
Reply #7
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...

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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...

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  • Last Edit: January 11, 2021, 12:48:23 pm by Roger & Susan in Home2

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?

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...

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Re: Auxiliary Air Pump frequently running
Reply #11
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...


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  • cdm
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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...

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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...

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Re: Auxiliary Air Pump frequently running
Reply #14


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...

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Re: Auxiliary Air Pump frequently running
Reply #15
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,...


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  • MarkC
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Re: Auxiliary Air Pump frequently running
Reply #16
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...

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Re: Auxiliary Air Pump frequently running
Reply #17
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

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  • MarkC
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Re: Auxiliary Air Pump frequently running
Reply #18
See Michelle's picture in Reply #7.  Ball valves work great.