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HWH aux air pump

Anyone venture to guess why my aux air pump (bags and bladder) would cycle more frequently when it warms up during the day, and slows or stops at night when it cools down?  I would think that cooler temps would promote leaks, not the other way around.  Any I deas to get me started in troubleshooting? 
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: HWH aux air pump

Reply #1 –
Sun on one side of the coach will heat up the air bags and tires on that side making it a bit higher than the other side.  If your level system is on auto it will try to level the coach usually by letting air out of the high side first and then adding air to the low side. 

Add an on/off switch for your compressor.  If your coach stays close to level good.  You can leave the level system on manual,and let some air out of the high side as needed.  Leaks are common and can happen anywhere.  Do,you have an air system diagram for your coach?
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: HWH aux air pump

Reply #2 –
Thanks Roger...that could be all it is and the bias on the controller is to add air vs. venting.  The pump runs about once every 6 hours at night and about every 5 minutes during the day.  I do have the diagram and without crawling under the coach, I have sprayed all the fittings and hoses I can reach with soapy water with no leaks found.
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: HWH aux air pump

Reply #3 –
If it runs Every 5 min there is a problem. If it's 5 min every 6 hrs , that is mine does and I have a leak that needs fixed at some point..

Running every 5 min is a big problem .. start looking for a leak .. start with the slide bladder if you have them and move on..

Re: HWH aux air pump

Reply #4 –
Thanks David.  Yeah, pretty sure I have a leak.  It's just periodic.

Was hoping someone would have some prior experience or insight into why the leak would become greater during the day, and basically seal up as it cooled down at night.  This is contrary to everything I've experienced with air systems...usually they get worse as it cools down.  Would like to target the culprit, and if it's the slide bladder, don't have the CB's to make repairs as I've had to get coach batteries, shocks and a solar system in the past 2 months.  :(  But would like to find a cause.

Other than soapy water or an acoustic system like FOT uses to find the leak, I guess I could dump the bags and see if it persists.  Then I'd know it's the slide bladder.  Sad, as the PO had the slide bladder (original) checked out at FOT in 2016.

Woody.

Quote from: DavidS –
If it runs Every 5 min there is a problem. If it's 5 min every 6 hrs , that is mine does and I have a leak that needs fixed at some point..

Running every 5 min is a big problem .. start looking for a leak .. start with the slide bladder if you have them and move on..
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: HWH aux air pump

Reply #5 –
Mine purges and adjust a couple times a day when hot and as it cools makes a couple more.. I'm at about 4-5 hours on the compressor coming in. Stays on for about 2 min and shuts off. Most times it's just twice a day.. I have a leaky leveling valve for sure. I climbed Uber it and started shooting all the parts underneath with soap and water and found 3 valves that were leaking so I replaced them. Fixed the cycling so after. Need to find the next larger ones and it will be close and I won't worry for the next few years. I have noticed the last couple times out my dash gauges are showing 99psi when they would barely break 90 psi at any given time. Not sure why ..

Re: HWH aux air pump

Reply #6 –

I added a valve and a pressure gauge to the line that runs to the bladder.  This way you see what pressure you have in the bladder (about 15psi) and then close the valve.  If the pressure holds your bladder is good.  If not there is a leak somewhere past the valve.  If it holds air but there is a leak somewhere else the vlave will keep pressure in the bladder and espnsure a seal (don't forget to open the valve before retracting or extending the slide). 

Lots of places for leaks.  The pressure protection valves on each of the main tanks, check valves, ride height control valves, and just about every fitting.  I have found this stuff to be pretty effective at leak detection, better than soapy water. 
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Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: HWH aux air pump

Reply #7 –
Thanks again Roger. I ordered some of the Snoop juice and will check into a valve/gauge on the bladder.  Woody.
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: HWH aux air pump

Reply #8 –
My thought is if you have a leaky bladder, it wouldn't matter if it's day or night, not just more during the day. A leak doesn't know what time of day it is. You definitely have something going on their but would be surprised if it's your bladder.
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel

Re: HWH aux air pump

Reply #9 –
I agree with Richard, hard to see how day/night would have any impact on a bladder leak. I think you should be looking at things that impact level first, tough to say when the difference between day and night is so great.  Every part and connection is suspect. 

If your level is steady or needs minor adjustment every few days, just shut the pump off.  Leaks are a way of life. Less stress
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: HWH aux air pump

Reply #10 –
When we got our coach I wasn't sure whether the aux compressor worked or not, as the coach seemed like it would lose air over a few days. We made a trip to Moscow, where they discovered a blown fuse and some leaks. They would only fix the leaks on their system, though. Since then more leaks have been fixed. I have heard the compressor run a time or two, but that's about it. Since replacing the air bags and two different searches for leaks (and finding some both times) the coach seems to stay pretty level for days, if not weeks, at a time.

The site we're on now has the coach sitting on the rear tires, while the nose is stretched up almost to the limit. After a few days, I noticed that the nose was starting to drop some, so I put some 2x8 planks under the front tires and releveled. NO drop since Thursday afternoon, so I think that maybe having the air bags stretched all the way out may have something to do with a leak that doesn't happen otherwise.

Re: HWH aux air pump

Reply #11 –
Pump update.  After 24 hours with pump off, coach stayed level and slide stayed inflated.  Turned the pump back on and it ran for a minute, shut off, and has been off for a couple hours.  I'd say my problem is a check valve or line between pump and tank?  Now to get my Snoop juice to work tomorrow, starting at the pump and working towards the tank, wherever that is.  BTW, my air system diagram in the owners manual doesn't help an iota.  Is there an HWH diagram I'm missing?  Woody.
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: HWH aux air pump

Reply #12 –
Air diagrams usually not in manual. Since you are motorcade James T can send it to you for your coach, call and make the request

Tim Fiedler
Gen-Pro.biz
630 240-9139
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: HWH aux air pump

Reply #13 –
Woody, here is the air schematic for 2001 U320 starting at build number 5871.  Yours is just before this.  There is another one also for 2001s starting at build number 5920.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: HWH aux air pump

Reply #14 –
Build# 5859
Scott & Carol Seibert
2001 42' double slide U320 - Sold
Previous - 2002 36' U320

Re: HWH aux air pump

Reply #15 –
Thanks, Roger...that's the same diagram I have.  I'm not sure what the flow path is for the 4 way crossings with a hash mark across the flow lines...check valve or cross over?  Not much help in finding where stuff is tho, and my exploratory skills are waning as I'm not as good as laying on gravel to search for stuff as I once was.  Where can I find the vacuum generator for the slide room and the aux storage tank?  Woody.
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: HWH aux air pump

Reply #16 –
On mine, the vacuum generator is on the driver's side, in the compartment below the slide on the right hand wall.  You can hear the air hissing when you turn the key on to the move the slide.  The tank is mounted under the coach to the rear of the generator.  You should see 3 tanks in that area.  Two for the brakes and one a slightly different shape and size for the HWH system. 

Hope this helps,

Rich
Rich and Peggy Bowman
2002 U270 3610 WTFS, build #5939--"Freedom"
2022 Jeep Grand Cherokee Summit 4xe
SMI AirForceOne brake system
PakCanoe 15

Re: HWH aux air pump

Reply #17 –
The 2002 is different from the 2001.  Look in the big bay on the driver's side on the inside of the carpet covered beam under the slide towards the rear. It is maybe 4"x6" with some hose connections, a solenoid and a regulator as I recall.  Compressed air flows across a venturi creating a vacuum to suck out air from the bladder.

I had a problem deflating mine one time, I pulled the line to the air bladder and just sucked on it,  bladder deflated.  If the air bladder manifold is working but no air from your compressor you can use any air source connected to the air supply line that will supply a continuous supply. 

A valve in the air line to the bladder and a pressure gauge (after the valve) helps know what is going on.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN
 

Re: HWH aux air pump

Reply #18 –
Does he understand what he is looking for? A picture might help him.. easier to spot.. Id get it but my coach is 300 miles away right now