Help Auxilary air pump is keeping all my service air tanks full

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Help Auxilary air pump is keeping all my service air tanks full

May 28, 2010, 07:49:25 pm

I guess I should re introduce my self since I am not usually called SusiQ (I feel a little like the guy in the transporter who had a fly travel with him), but I digress. I have a 02 U320 that is keeping all my air tanks filled when I am dry docked. I wonder if I have a bad selenoid or relay because is behaves like I left the air tank switch on. Are there any check valves? And then there is the bigger question where are all these gadgets. Thanks for the help ahead of time.

Art & Polly
12986
02 U320 40'
apj1944@gmail.com

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #1 – May 28, 2010, 08:18:30 pm

Quote from: SusiQ – May 28, 2010, 07:49:25 pm

I have a 02 U320 that is keeping all my air tanks filled when I am dry docked.
Your aux compressor is supposed to keep them filled if the pressure goes down.

I wonder if I have a bad selenoid or relay because is behaves like I left the air tank switch on.
What exactly is it doing?

Are there any check valves?
Yes there is. a large one at the output of the aux compressor.
Another at each of the front & rear tanks where the aux compressor air line # 57 ties in.

And then there is the bigger question where are all these gadgets.
Which ones??

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #2 – May 29, 2010, 01:03:35 pm

Hi Barry, When we are drydocked pressure tank 1 & 2 are kept at 115 all the time. They usually leaked down and when we broke camp and I started the engine the air pressure would come up. It was my thought that when parked the air compressor kept the HWH air tank full only. The only problem with what it is doing is the battery draw for a much longer period of time since it is pressurizing the entire system. I was thinking that the air tank switch on the console used to bring up pressure discretely prior to leaving a campsite had a normally open or closed relay that was sticking. Thanks

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #3 – May 29, 2010, 01:44:16 pm

Quote from: SusiQ – May 29, 2010, 01:03:35 pm

When we are drydocked pressure tank 1 & 2 are kept at 115 all the time.
They usually leaked down and when we broke camp and I started the engine the air pressure would come up.
Sorry Art, I am still having difficulty understanding what is wrong.
The above statement is correct. if your tanks are not full when you start the coach the engine compressor will fill them up.

It was my thought that when parked the air compressor kept the HWH air tank full only.
You are referring to the Aux 12vdc air compressor?
When you say HWH tank only, are you meaning the tank for the slides or the tanks for the leveling or both?

The only problem with what it is doing is the battery draw for a much longer period of time since it is pressurizing the entire system.
There is a pressure switch on the Aux Compressor that will tell the compressor when to come on & off.
Around 80 - 115 psi.

I was thinking that the air tank switch on the console used to bring up pressure discretely prior to leaving a campsite had a normally open or closed relay that was sticking.

This is just a ON/OFF switch, not a relay.

With that said:
Am I understanding you to say your problem is,
You are loosing air on your primary & secondary air tanks: (The 2 pressure gauges on your dash)
And that the 12vdc Aux Compressor is coming on too often draining your batteries while dry camping?
If that is what you are saying, how low does the pressure gauge get before 12vdc aux compressor comes on?
What pressure on the gauge does the 12vdc aux compressor go off?
How long does it take for air pressure on the pressure gauges to show low enough before the 12vdc Aux Compressor comes on to fill it?

If you hit the "Emergency Stop" Button on the HWH control panel it will go to sleep and not try to re level every 30 minutes. That may slow down how often the 12vdc aux compressor comes on. I have had to do this while I was troubleshooting my air leak.
My compressor was running so much it kept tripping the resettable circuit breaker in the utility bay.

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #4 – May 29, 2010, 02:15:59 pm

Where would the 12v air pump be located on a 99 u320 40ft. I can't seem to hear any thing running. thanks jc

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #5 – May 30, 2010, 03:35:40 pm

My aux air compressor is keeping my primary and secondary tanks at 115 all the time, even though the air tank switch on the console is off. In the past it only refilled the tanks on the slide and levelers filled. Now at 80 psi in the primary and secondary tanks it starts to run and shuts off at 115 or so.

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #6 – May 30, 2010, 04:05:15 pm

I see what you mean now.
Lift out the Air Tank Rocker Switch & remove the wire #9710 from the switch.
The number is stamped on the white wire.
That completes the circuit to air up the pressure gauges.
It sounds like the switch is stuck on "ON"

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #7 – May 31, 2010, 07:32:25 am

On the '99 U320 the aux air compressor is located behind the inverter in the second bay on the street side.

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #8 – May 31, 2010, 12:40:03 pm

Thanks I'll try that and see if it stops, Will let you know though it will be in a week or 2. Again thanks to all.

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #9 – July 16, 2010, 10:08:03 pm

I decided to reopen this thread since I have the same issue. Namely, my 12v compressor runs to fill the brake tanks even though the "air tank" switch next to the driver's position is in the off position. The switch tests ok.

Per my air schematic, line #76 ( 3/8") runs from the compressor to the wet tank, and I can physically see line 76 coming from a valve (I presume it's a valve) right at the compressor. I don't find the air tank switch on my electrical schematic, (or that valve on any schematic either) so I'm not sure if that's the valve being controlled by the air tank switch. Is there any other device on that line to the wet tank that could be the culprit? How can I test the valve in question?

Thanks,
Mike Spitz
2003 u-295

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #10 – July 16, 2010, 10:57:52 pm

Quote

My 12v compressor runs to fill the brake tanks even though the "air tank" switch next to the driver's position is in the off position. The switch tests ok.

Per my air schematic, line #76 ( 3/8") runs from the compressor to the wet tank, and I can physically see line 76 coming from a valve (I presume it's a valve) right at the compressor. I don't find the air tank switch on my electrical schematic, (or that valve on any schematic either) so I'm not sure if that's the valve being controlled by the air tank switch. Is there any other device on that line to the wet tank that could be the culprit? How can I test the valve in question?

If your Rocker switch is OK than it may be the #2 solenoid is stuck open.
Here is the electrical diagram that might help.

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #11 – July 17, 2010, 10:28:35 pm

Barry,
thanks for that scematic.

How did you know it's the right one - I find the HWH site confusing. I saw the picture of your slide mechanism on another topic. Mine looks the same and I gather from your comment there that all 2003 coaches have the same system. But, what's it called? In other words, is there something more specific than Series 2000?

Thanks,
Mike Spitz
2003 U-295, #6063

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #12 – July 17, 2010, 11:03:47 pm

Quote

How did you know it's the right one - I find the HWH site confusing.

We have the same year coach so i figured the schematic was the same as mine.

Quote

Mine looks the same and I gather from your comment there that all 2003 coaches have the same system.

I had an early 2003 & he had an older 2003 so I figured all the ones in between were probably the same.

Quote

But, what's it called? In other words, is there something more specific than Series 2000?

Our HWH System is a series 2000.
Are you looking for the manual?
I can send you a copy.

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #13 – July 21, 2010, 10:15:18 pm

Barry,
Sorry for the delayed response - I've been otherwise engaged for a few days.

I had printed a manual off HWH's website some time ago, but it didn't include that page, so thanks.

I disconnected the air line from that solenoid (2) and was surprised to find air coming back out the hose under pressure. This is the line that goes from the aux compressor to the wet tank and my FOT schematic shows a check valve that should prevent air from coming back out of the wet tank. Apparently, the check valve is bad, but I don't see how that would cause the compressor to run to fill the wet tank when the "air tank" switch at the driver's seat is in the off position. If I'm analyzing this correctly, both solenoid(2) and the check valve must be bad.

Since the compressor switches off when the air tanks get to about 95psi, I can be sure the pressure switch is not part of the problem?

Also, what is the proper sealant for thread on these brass fittings throughtout the air system? On mine, I see some yellow, some red and some with teflon tape. The last surprised me in light of the recent discussion about it's use on tire valves.

Thanks,
Mike Spitz
2003 u-295 #6063

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #14 – July 21, 2010, 10:38:49 pm

Quote

Apparently, the check valve is bad, but I don't see how that would cause the compressor to run to fill the wet tank when the "air tank" switch at the driver's seat is in the off position.

I dont think it would either

Quote

If I'm analyzing this correctly, both solenoid(2) and the check valve must be bad.

I believe the Solenoid 2 is the problem.
I am not sure exactly where you removed the air line to say for sure that you have a bad check valve.

Quote

Since the compressor switches off when the air tanks get to about 95psi, I can be sure the pressure switch is not part of the problem?

If it is coming on & going off within those parameters, I would say the pressure switch is operating properly.

Quote

Also, what is the proper sealant for thread on these brass fittings throughtout the air system? On mine, I see some yellow, some red and some with teflon tape. The last surprised me in light of the recent discussion about it's use on tire valves.

James Triana told me I could use Teflon Tape.

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #15 – July 22, 2010, 09:43:52 am

I did not see any response that seems to apply. In y 01 320, the air pressure gauges are 12vdc, and when you turn off the key switch, they simply stay where they were. Let is sit for a few days, turn on the key, let gauges go through their routine, then they will read actual pressure as is now.

Maybe other gauges are direct reading (Mechanical), they tell what is now.
Give it a try.
Dave

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #16 – July 22, 2010, 10:51:33 am

Barry,
I disconnected the air line right at the solenoid(2) with everything off. Pressurized air came back out of the line for a considerable time until I reconnected. I think I had it off long enough for the line itself to have exhaled its air, so I'm assuming the air was leaking back out of the wet tank.

Dave M,
If you're referring to my issue, I was watching gauges, with ignition key on, while 12v compressor ran. The 12v compressor brought both brake tanks from about 30psi up to about 95psi even though the switch by the driver's position is in the off position. The switch tests good with my meter. This has been going on for couple months - first discovered when I saw 12v compressor breaker had tripped.

Thanks
Mike Spitz
2003 u-295, 6063

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #17 – July 22, 2010, 10:58:04 am

Got ya, I am clueless why the pump is running without being turned on, or some clown has rewired around that switch. Surely the pump is getting juice from some circuit, that is being fed by the breaker that tripped. It ain't normal for electric things to run with out power I have found.

Good luck
Dave

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #18 – July 22, 2010, 11:28:45 am

Quote

I am clueless why the pump is running without being turned on

Dave,
On our 2003 the Aux compressor is activated with a pressure switch.
When the psi gets to about 70-80 it activates the compressor for leveling and the slides.

What Micheal's issue is,
It is also filling the brake tanks which should only be activated by the dash rocker switch which opens solenoid #2 which appears to be bad.

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #19 – July 22, 2010, 02:50:00 pm

Hi Barry, My old 01 320 does not have a switch on dash for the compressor, so like the ex gov of IL., I talked too much on that subject.

Thanks
Dave

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #20 – July 22, 2010, 08:58:32 pm

Well, only thing I can add is more questions, but they are on topic. My 96 u270 also doesn't have a rocker switch either. I assume the purpose of the rocker switch is for emergency use, such as if you lose the main air? So I have no way to release the spring brakes if the main air fails? Also, my air gauge has a white pointer and an orange pointer. What's with that?

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #21 – July 22, 2010, 09:17:48 pm

Quote

I assume the purpose of the rocker switch is for emergency use, such as if you lose the main air?
So I have no way to release the spring brakes if the main air fails?

I think it is so you can air up the brakes without turning on the engine for 5 minutes.

Re: Help Auxilary air pump is keeping all my service air tanks full

Reply #22 – July 23, 2010, 06:47:16 pm

Quote

I disconnected the air line right at the solenoid(2) with everything off.
Pressurized air came back out of the line for a considerable time until I reconnected.
I think I had it off long enough for the line itself to have exhaled its air, so I'm assuming the air was leaking back out of the wet tank.

I could not find #2 Solenoid on my air Diagram
be_2254_2002_03_21 Air Schematic
So I had to email James to find out where it was.
It is NOT on there.
It should be on line 76 in front of the check valve.
I think they put it on starting in 2003

Sooo that line would be hot (Pressurized Air in line)
That is why you had air coming out.
I don't think you have a check valve issue now.
I think #2 solenoid replacement should get you back in action.

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