My auxiliary HWH air compressor will not shut off-HELP

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My auxiliary HWH air compressor will not shut off-HELP

January 13, 2023, 04:03:35 pm

I purchased a used 2007 Foretravel Nimbus 336 in February of 2019-I'm a full timer. My very first Foretravel-I'm hoping it will out live me. I have a current problem that I don't know how to fix or even what my be causing the problem. When I'm parked the HWH Auto leveling system keeps my coach level-checking it ever 30 minutes. When it needs to be re-leveled it adjust the appropriate air bags and the coach is level again-this usually happens with I move about in the coach. Usually during this process my auxiliary air compressor comes on to replenish the air pressure-I'm not sure whether this is for the main air tanks or some auxiliary air tank??? Sometimes my auxiliary air compressor comes on even if the coach is not re-leveling. Well, late last night my auxiliary air compressor came on even though my coach didn't need to be re-leveled and it would not shut-off. It ran for at least 45 minutes. I have had similar problems in high altitude, but currently that is not the case. The ambient temperature last night was in the mid 30's, so I though this might add to the problem-but I tried running the auxiliary air compressor after it warmed up, but it still would not shut off after 30 minutes. I don't want to run it more than 30 minutes for fear it will overheat. Any suggestions?

Thanks In Advance,

John

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #1 – January 13, 2023, 04:37:43 pm

Not shutting off is indicative of a leak or a bad pressure switch.

When the aux compressor is running, can you hear air escaping anywhere - particularly around the slide bladders and the unloader solenoid valve that's on the bottom of the clear condensate bowl at the aux compressor itself?

The aux compressor running when not actively leveling could be either for the slide bladder tank or something in the slide bladder air plumbing.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #2 – January 13, 2023, 05:54:04 pm

Is there a pressure gauge on your system, so you can see how much pressure is in the HWH tank and lines? WIthout knowing if it's running because of pressure or possibly a stuck solenoid, relay, etc, it's harder to troubleshoot.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #3 – January 13, 2023, 07:25:36 pm

Thank You for the reply. If there is a pressure gauge for the HWH tank I don't know where it is, I don't even know where the HWH tank is on my coach-sad to say!!!

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #4 – January 13, 2023, 07:28:36 pm

Usually the gauge would be near the pump, after the check valve so the gauge sees the tank pressure.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #5 – January 13, 2023, 07:33:32 pm

That clear bowl ~~front and center of Keith's photo~~ [see Geodmann's post below]is the one with the unloader solenoid valve at the bottom. That bowl and the unloader valve seat are known to be problematic. If either leak, they prevent the aux compressor from building pressure, which would cause the compressor to run non-stop.

That valve is normally open when the compressor is off. When it runs, the valve closes, and when the compressor is done, it opens with the "whoosh/pshhhhh" you normally hear at the end of the aux compressor run. That blows out most of the condensation in that bowl. The seat on that valve can collect debris. The bowl itself can develop cracks due to thermal shock when the unloader valve suddenly opens. We saw a catastrophic failure of that bowl on a 2008/9 Nimbus several years ago (Steve helped the owner diagnose the problem when FOT had no openings in service for several days).

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #6 – January 14, 2023, 09:02:07 am

Small clarification to Michelle's comment. The purge valve in the photo is actually on the second clear bowl visible in the background behind the pressure switch and next to the dessicant bowl. The clear bowl front and center has a manually operated drain valve on it. Many have added a pressure gauge to the system (also visible in the photo) to help in troubleshooting and that is easily done and highly advisable.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #7 – January 14, 2023, 09:31:12 am

Quote from: Geodmann – January 14, 2023, 09:02:07 am

Small clarification to Michelle's comment. The purge valve in the photo is actually on the second clear bowl visible in the background behind the pressure switch and next to the dessicant bowl. The clear bowl front and center has a manually operated drain valve on it.

Thanks for the correction - yes, wrong clear bowl (it's been a few years since I've been around an aux compressor

) I edited my post to avoid confusing anyone.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #8 – January 14, 2023, 09:42:20 am

John, kinda back tracking but have you keep up with dryer service? Annual desiccant replacement? If you have great please disregard my post. If you haven't you may have contaminated your system with decomposing desiccant. It will cause all of your problems and more.
Scott

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #9 – January 14, 2023, 09:48:42 am

Quote from: dsd – January 14, 2023, 09:42:20 am

John, kinda back tracking but have you keep up with dryer service? Annual desiccant replacement? If you have great please disregard my post. If you haven't you may have contaminated your system with decomposing desiccant. It will cause all of your problems and more.
Scott

Open the tank drains. If anything but clean, dry air comes out, the air dryer has FAILED.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #10 – January 14, 2023, 10:03:03 am

I want to thank everyone for the feedback. I have the air dryer serviced annually and I frequently change the desiccant. See the attached photo. Is the item identified with the red arrow the purge valve? It appears this item is connected to 12 volt power and even with the auxiliary HWH air compressor completely disconnect and not running this device is extremely hot to the touch-Is this normal?

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #11 – January 14, 2023, 10:06:42 am

Yes that is the purge valve. That valve should be normally open with no power when the compressor is off and energized when the compressor is on to close it and allow the compressor to build pressure. If it's extremely hot it sounds like it's been energized for a long period of time.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #12 – January 14, 2023, 10:21:39 am

Yup, that is the aux compressor purge valve. Normally open and closes with 12v. If it's hot to the touch with compressor off, then the Essex relay has failed or it's simply not wired properly. See attached schematic.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #13 – January 14, 2023, 10:31:15 am

Woody makes a good point. In order for the purge valve to be hot it must be receiving 12 volts but you say the compressor is not running and they are both energized from the same terminal on the Essex relay. When you say your compressor is completely disconnected how have you turned it off?

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #14 – January 14, 2023, 10:43:37 am

I have placed a 30 amp in-line fuse that delivers 12 volt power to the auxiliary HWH air compressor. Thus, when the compressor will not shut off and constantly runs I pull the fuse.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #15 – January 14, 2023, 12:38:30 pm

If you've installed that fuse on the wire going from the Essex relay terminal number 2 directly to the compressor then you haven't prevented the Essex relay from pulling in and energizing itself and the purge valve. Both of those will be drawing current therefore potentially draining your batteries and wearing out those devices. Worst case scenario The heat could present a fire hazard. The wiring diagram shows a 15 amp fuse on the wire that brings 12 volts to the Essex relay. It's better to pull that fuse to ensure that nothing has voltage present.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #16 – January 14, 2023, 12:41:39 pm

John your original problem is that your compressor is not shutting off. Therefore either you're not able to build pressure or the Essex relay is stuck closed. If you're not building pressure that should be a fairly easy leak to find and it may be the purge valve on the bottom of the filter bowl that was mentioned in reply #5. If that has air coming out of it while the compressor's running then it has not closed and you will never build pressure.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #17 – January 14, 2023, 03:02:35 pm

Again thanks to everyone responding to my issue. My system is not wired like the schematic provided. See Attached photo and numbering. Number 1 is a mini circuit board attached to my Essex Relay. My purge valve is connected to the mini circuit board-a fused connection-number 2. The other line from the purge valve number 3 is connected to the Essex Relay terminal as indicated. The line with the 5 amp fuse Number 4 goes from hot terminal of Essex Relay to a multi connector-I have no idea where it goes. Removing this 5 amp fuse has never shut off the compressor when it is running and won't stop. Number 5 is the incoming "hot" line. Number 6 goes to the positive side of the compressor. Number 7 goes to the negative side of the compressor. In the past whenever the compressor would run and not stop in a timely manner I would have to disconnect line number 7. I have placed a 30 amp fuse in line number 7 so I can just remove the fuse rather than disconnect the wire. When I bought this coach in Feb of 2019 this is the way it was wired. Except for a few occasions (like high altitude and discovering some air leaks) it as seemed to work OK until just this week. I don't have the skill set to try and which around a bunch of wires. I have to assume the mini circuit board is meant to be there. I am going to try and change out the purge valve, but anything beyond that is beyond my skill level. I will update whether or not changing the purge valve solves the problem.

Thanks Again

John

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #18 – January 14, 2023, 03:21:09 pm

John, from my perspective, I'd assume that since it was working correctly before this week, that it's likely not a wiring problem, but more an air issue. Your pump cannot generate enough volume/pressure to fill the tanks to their preset pressure. This indicates a leak. Connect everything back up and let the pump run for a bit...maybe 10 minutes. Then kill the power and listen for leaks. Use that 10 minutes to find a water bottle and dump in some dish soap. Shake and apply to every fitting and connection you can see with air lines, especially if you hear air leaking. Tighten/replace any leaking areas/fittings and then let the pump run again.

Adding a gauge wouldn't be a bad idea either.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #19 – January 14, 2023, 10:05:10 pm

While the compressor is running put your finger over the discharge port on the purge valve. If there is air coming out then you have found the problem. You can screw a 1/8 inch pipe plug into the purge valve and that will stop the air from coming out. The mini circuit board on the Essex relay is supposed to be there. Its function is to activate the compressor if the leveling system calls for air. Taking out the 30 amp fuse you put in doesn't disconnect the power to the purge valve. There is a 5 amp fuse that if you take it out will keep the compressor from running unless the level system needs air to raise the coach to level. There are 2 5 amp fuses. In this area. When the compressor is running, try pulling each one, one at a time and then you will know how to stop the compressor from running without removing the 30 amp fuse.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #20 – February 11, 2023, 04:02:19 pm

Sorry it has taken me so long to post my update.

This is an amazing Forum. Great Members with a comprehensive wealth of knowledge and the willingness and kindness to share it.

Based on the responses I got I discovered the old HWH RAP 6354 Solenoid Value (purge valve) it fact had failed. When the auxiliary air compressor came on the valve was blowing air out of the back of it-meaning the valve was not closing as it should. I removed the poly bowl with the bad attached purge valve. I also discovered, as suggested by the responses, the base of the poly bowl where the purge valve attaches had numerous cracks in it. So even before the purge valve failed the poly bowl had been leaking air. Which accounts for the compressor running for a long time before shutting off and running more frequently than normal. HWH does not recommend running the auxiliary compressor more than 3 to 6 minutes (depending on the size of the compressor) without shutting it of for 30 minutes to let it cool down & not overheat-I violated these parameters often-I guess I'm fortunate the compressor still works. In case I need to shut off the compressor in the future I have installed a 12 volt ON/OFF Switch between the house batteries and the 12 volt Essex Relay-I removed the 30 amp fuse I had previously installed-see Image.

As a temporary fix (as suggested by the responses) I replaced the cracked poly bowl, salvaged the old connector for the purge value and plugged the connector with a 1/4 inch NPT Plug. I wasn't able to find a new connector without buying a complete new poly bowl assembly. Hope the old one will continue to work.

I ordered a new purge valve from Northwest RV Supply. The part was shipped directly from HWH. When I got the part the box was labeled with the correct part number but it contained the wrong Solenoid Valve-which caused further delay. HWH had to search through their boxed inventory to make sure what was on the box label was actually in the box before they would ship anymore items-according to Northwest RV Supply this had also happen to another one of their customers-I was the first.

I finally got the correct Solenoid Valve, installed it and everything seamed to be working correctly-see image.

But as suggested by the responses I got, I probably should also install a pressure gauge. So I ordered brass fittings and a pressure gauge from Amazon. Got them installed and I could see I was leaking air. So I got some leak detector and discovered at least 4 of the brass fittings I installed were leaking-I used teflon tape on all fittings-but still had air leaks. So I started all over, got a better quality air gauge, and the second time I used both teflon tape and Rector Seal #5. I first applied the Rector Seal #5 and then placed teflon tape over it-see image. I checked for air leaks on these fittings-none. However, even now I'm still leaking some air. But being almost 76 I don't feel like crawling around under my coach trying to find the leak or leaks. If the auxiliary compressor does not run frequently and not very long, I may not do anything. If the leak or leaks need to be address, I will have a service center handle it.

I want to thank everyone again for your Responses & Advise,

John

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #21 – February 11, 2023, 06:16:56 pm

Thanks for the follow up. Great write up and pictures. This will be great for future reference.

Richard

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #22 – February 11, 2023, 08:51:21 pm

I have just started having air leaks and none of them have been at the air compressor. I have had all 4 of the shut off valves to the slide controls leak, two of the tank drain fitting above the valves leak, a few 3/8" fitting leak, and 2 PPV valves leak.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #23 – February 12, 2023, 10:51:26 am

Teflon tape fails. A good quality pipe dope has never failed on me and I have done a lot of
plumbing.

Re: My auxiliary HWH air compressor will not shut off-HELP

Reply #24 – February 12, 2023, 01:10:56 pm

I sure hope you left at least two threads exposed from the Teflon tape when you wrapped the threads. Nothing worse than having Teflon tape pieces injected into your air system. And I agree with old guy about the tape.

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