compressor "cycling" every two minutes

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compressor "cycling" every two minutes

December 05, 2017, 12:04:32 am

We are in Port Aransas on our third month of an eight month trip in our coach. My wife woke me to tell me the coach was loudly letting off air every two minutes or so. It was annoying her and our neighbors. We are on a very level pad. I turned the leveling system "off", thinking this might stop the cycling. It didn't. I had to crawl into the big storage area on the drivers' side, and disconnect the hot wire to the compressor, which is under my slide. The compressor would run hard for a few moments, then the system would let the air out in a loud " whoosh". I have no idea what is going on or how to remedy the situation, but we have a long way to go on this journey. Anyone know what's happening here?

Thanks. BTW.....when we were at OTM, I explained a similar situation to Wayne. He had me raise the coach, then he and I went under the coach with a soap spray and checked for leaks. He found none. I had been parked on a slope the previous night, and he said that might have caused the cycling. Told me to turn off the leveling system if that happened again. It happened again. NO slope.

!!!!

Re: compressor "cycling" every two minutes

Reply #1 – December 05, 2017, 12:20:13 am

OK, what you are hearing is likely the purge valve which opens automatically at the end of the small compressor run cycle - it will make that sound every time that the small compressor shuts off.

First and foremost, shut off the petcock in the basement that feeds air to your slide bladder (it will be mounted in the bay below the slide and on the vertical wall that extends down into the bay in all likelihood) - and plug back in the small compressor.
If the pressor does not change behavior - breath a HUGE sigh of relief, as you probably do not have a bladder leak. A large bladder leak can cause the issue that you describe, as the bladder system (HWH) continues to want to keep the bladder inflated even if the level system is shut off.

Not a bad idea to leave the petcock shut off overnight and see if the bladder stays inflated - JUST REMEMBER TO TURN IT BACK ON BEFORE YOU GO TO TAKE IN THE SLIDE!!!!! because with it in the closed position of course the slide bladder will not deflate when you go to run in the slide with expensive results.

There are two check valves in the system near the small compressor (if you r system is like mine). If you are motorcade member call and get James T to send you the Air digram for your coach- it will show all the locations of all the check valves - the one you are looking for is brass with about a 1 1/4 diameter, somewhere near the pump on the largest sized air line leaving the pump. If that one has become slightly obstructed, your pump will short cycle" as that 3-4' pice of tubing is filled and then the air leaks past the bypass at that point and the process repeats.

Check the records, find out the last time the air dryer was serviced or replaced. Desiccant in the air system causes all sort of Gremlins - including stuck check valves. If no records available have it checked ASAP - I recommend an entire replacement of the unit (Around $550 for a factory reman) in lieu of a rebuild.

Most of this sort of stuff is intimidating to a new owner, but it gets less stressful after you work through a couple of on the road events. Learning curve.

Tim Fiedler

Sure Start Soft Start

TCER Direct generator-gas-prod 630 240-9139
Gen-Pro

Re: compressor "cycling" every two minutes

Reply #2 – December 05, 2017, 12:33:08 am

Thanks.Will do. Air dryer was just redone. The bladder is new. I hope no leak there also! Will check tomorrow.

Re: compressor "cycling" every two minutes

Reply #3 – December 05, 2017, 01:25:43 am

Glenn, Tim has explained the things to try. Isolating the bladder is one of the best things to try. And since you took it out of level mode, I understand you still have frequent cycling of the auxiliary compressor. Any idea of how long the auxiliary compressor runs when it does run? Maybe 3.5 minutes and then it shuts off with the swoosh sound.....or does it take much longer than that, maybe five or seven minutes, to build up the pressure and then shut off?

Note this, a leaking check valve does not in my mind respond to soapy water.....which shows leak to the atmosphere, not a leak of the check valve which allows air to leak back in the direction it is supposed to be protecting against the air flowing. If it is leaking air back in a direction it is not supposed to do, there may be ways to detect that, such as with dash gauges. But do you have an air pressure gauge on your auxiliary compressor so you can see the behavior of the tank that it feeds? That can be helpful if you have had such added. While at it, add a toggle switch to the aux compressor so you can easily turn it off, not have to pull the fuse.

When you had the new air dryer redone, why did you do it? Was there white dust coming from any of the four air tanks when you test drained air from each and therefore you replaced the air dryer? IF so, then you have to suspect residual desiccant still in your air system. More on that later, but as Tim said, it can play havoc with the system That needed to be cleaned out, IMHO, if there was a lot of desiccant blowing out when exhausting.

I have a souvenir check valve that i have kept to remind me of what a little moisture and some desiccant can do to ruin a check valve.

If want to talk, give me a call.

Re: compressor "cycling" every two minutes

Reply #4 – December 05, 2017, 08:38:38 am

I had the dryer routinely serviced last May. What I don't understand is when I locate the check valve, what am I then supposed to do?? Do I remove and clean or remove and replace ?? Where would I buy one?? The bladder is still ok this morning ( just got up and haven't gone into the basement yet ) and has been working fine. It was replaced by the PO not long ago. The compressor ran a short time, maybe a minute, then releases air. I appreciate all the help I can get.

Re: compressor "cycling" every two minutes

Reply #5 – December 05, 2017, 08:44:15 am

If the air compressor has any kind of a tank try draining it if it's waterlogged it will cause short cycling

Re: compressor "cycling" every two minutes

Reply #6 – December 05, 2017, 10:40:46 am

You do have a tank for the aux compressor...and on bottom of it a valve to drain or usually just open a second see if blows out water, or dust. Hopefull no dust.

If you are new to this, lets talk how check all four tanks and frequently! Will send you pm for my phone

Re: compressor "cycling" every two minutes

Reply #7 – December 05, 2017, 11:33:26 am

Just went into basement.
Tim....could NOT find petcock to bladder. Bladder is still ok this morning. IF I isolated the bladder and reconnected the hot wire, what did you mean by "....if the compressor does not change behavior...??"
I could NOT locate the tank for this small compressor.

I have the air schematic in the owners manual, but cannot make sense of it, or understand what I am trying to find and what to do if I find it.

Thanks, everyone, for helping me with this.

Re: compressor "cycling" every two minutes

Reply #8 – December 05, 2017, 11:41:45 am

In the 01, there is a third air tank up under the front end of the coach. Each of the three tanks as valve on bottom. I had my valves moved to the fender of the coach so easy to check.

As for the valve to the bladder, open the bay behind the fuel bay on driver side, find the bay with the electronics panel on the left as look in the bay and then, in the bay look up high on the rear wall of that bay, near the door. and you will see an air line with a simple 90 degree valve. Turn it 90 degrees and will cut off air to the bladder. That valve itself is bad about leaking!

If not working to help you find, you or Tim let me know and will send you photo.

There is another area in that can leak too and maybe I will post a photo of that but try the valve first

To check bladder, trying gently sliding a credit card between the bladder and the coach wall. If the bladder has a leak, it can appear full and even feel full to the touch so the credit card test is good versus looking for light or even feeling with your fingers

m

Re: compressor "cycling" every two minutes

Reply #9 – December 05, 2017, 12:11:29 pm

Just spoke with John and Mike and they were both helpful.
UPDATE....I think I found the petcock located off a metal boxlike thing. I ALSO found what looks like a little glass condensate collector with a brass valve on it with a wire. When I reached my hand to see if I could purge the glass the brass valve almost burned my fingers !!!!! It was VERY hot, even though the compressor has been disconnected all night and up until now. I think my problem is related to this valve. Who should I call? What should I do next?? Is it ok to reconnect the compressor when we have to leave here in a week??

Re: compressor "cycling" every two minutes

Reply #10 – December 05, 2017, 12:23:05 pm

Quote from: GleamB – December 05, 2017, 12:11:29 pm

Just spoke with John and Mike and they were both helpful.
UPDATE....I think I found the petcock located off a metal boxlike thing. I ALSO found what looks like a little glass condensate collector with a brass valve on it with a wire. When I reached my hand to see if I could purge the glass the brass valve almost burned my fingers !!!!! It was VERY hot, even though the compressor has been disconnected all night and up until now. I think my problem is related to this valve. Who should I call? What should I do next?? Is it ok to reconnect the compressor when we have to leave here in a week??

That is a solenoid valve, should have a plug connection on the hot side. Just unplug it.

Re: compressor "cycling" every two minutes

Reply #11 – December 05, 2017, 12:27:36 pm

" Just unplug it??" and THEN what?? Adam at OTM says it's a condensate valve gone bad and should be replaced. Does anyone know where I get one? Is that what I ask for? How hard is it to R/R?? Where doe the condensate go...into my storage bay??

Re: compressor "cycling" every two minutes

Reply #12 – December 05, 2017, 12:38:51 pm

Quote from: GleamB – December 05, 2017, 12:27:36 pm

" Just unplug it??" and THEN what?? Adam at OTM says it's a condensate valve gone bad and should be replaced. Does anyone know where I get one? Is that what I ask for? How hard is it to R/R?? Where doe the condensate go...into my storage bay??

Part # RAP6354 solenoid,n/o 1/8" 150 PSI SNGL. But any 12 volt n/o 1/8" solenoid should work. If it is leaking when compressor running, you can try cleaning it, may be trash in seat. Should close when pressure is low, this is why it is hot when low pressure and compressor not connected.

Re: compressor "cycling" every two minutes

Reply #13 – December 05, 2017, 01:05:56 pm

just turn it off, let it rest, reconnect and see if clears.....mine did, as we discussed.

for you to turn off, as discussed, you may pull fuse or plug in wire (as Jim said).....I have switch after market...but heater solenoid affair was so hot on mine I figured was draining a battery! I would not rush to order a new one without trying this first.

and as we discussed, there may now or sometime be leak in the condensate system collection/discharge system and if so it can require a new cylinder (they crack) or sealant. You can do that if you are flexible enough. Symptom of leak is slow to reach full 85 psi, long time to reach it (10 minutes) and cut off.

You can also, as we discussed, have a leak via the front third tank but I suspect that less likely for you at this point.

as for the valve to the slide, in the first photo it is in the middle the photo, brass fittings on air line, slanted down at 45 degree angle, partially hidden behind the wires and tubes.....but know that mine, as we discussed, is a replacement and the original not that much brass. Common leak point.

another place to leak is on the aluminum block, you do not often see leaks there but can happen on the black cylinder affair.

mike

P.S. I did not include photos of the aux compressor with gauges, switches and the condensate....are on other posts but can bring them to here if need.

Re: compressor "cycling" every two minutes

Reply #14 – December 05, 2017, 03:50:49 pm

With the DC compressor running, you might check to see if you feel any air escaping from the solenoid drain - just the bottom of the solenoid. Just a slight puff is enough to reduce the build up of full pressure. It might be slight feeling and making no noise. If so you indeed have a poor sealing of the solenoid. As already mentioned, take it off and disassemble it to clear any debris. Also as a temporary fix while apart you might flatten the rubber seal by spinning a new pencil eraser on it - to make the plunger seat better.
The solenoid might have been very hot because the compressor has been running so long from lack of the solenoid sealing fully.

Re: compressor "cycling" every two minutes

Reply #15 – December 05, 2017, 04:22:59 pm

Quote from: GleamB – December 05, 2017, 12:27:36 pm

" Just unplug it??" and THEN what?? Adam at OTM says it's a condensate valve gone bad and should be replaced. Does anyone know where I get one? Is that what I ask for? How hard is it to R/R?? Where doe the condensate go...into my storage bay??

I got one 2 weeks ago from HWH, they have the exact replacement... $120. I'm at work and the part number is at home. it opens when the compressor is off and closes when it is off. MOT looked at it last Friday also and replaced the bowl that it is attached to, the fitting that the valve screws into was cracked to... notice the hot wire to the compressor is cut to get the compressor to stop running...

Re: compressor "cycling" every two minutes

Reply #16 – December 05, 2017, 04:28:31 pm

Mine was doing the same thing and I found a major leak at the solenoid that looks like one of the six pack. The O-ring was very brittle.

Re: compressor "cycling" every two minutes

Reply #17 – December 05, 2017, 04:31:10 pm

Quote from: qcj – December 05, 2017, 04:28:31 pm

Mine was doing the same thing and I found a major leak at the solenoid that looks like one of the six pack. The O-ring was very brittle.

which solenoid?

Re: compressor "cycling" every two minutes

Reply #18 – December 05, 2017, 05:03:55 pm

it is the solenoid that releases the air thru the glass condensate cylinder, out the bottom at a right angle as I recall. the photo by the posts just above show that.

that system is prone to leaking, that is to say, it among the first places to look for a leak.....the cylinder affair.

and better there than a slide......I do know that, one is change, the other is coach bucks.

but may not need to replace it, try cycling it first, see if clears the solenoid. But if the glass cylinder is cracked or fit ruined, just need to replace. May be able to feel the air with our hands but certain the soapy water bottle spray will show the way

Re: compressor "cycling" every two minutes

Reply #19 – December 05, 2017, 08:12:19 pm

hdff .......THAT IS THE PART that I am talking about. It is VERY HOT to the touch, even though the compressor had been off for hours. I will take it apart, after running the compressor again, and see if there is a leak there. What I still don't understand is......if the glass part collects moisture, as with most air compressors, then WHERE DOES THE CONDENSATE GO???!!! I found a post written by Carol and Scot in 2013 that shows a picture of the solenoid, only HIS HAD A PETCOCK ON THE END OF THE SOLENOID. I can understand having to empty moisture from the compressor.....I have been doing that for years on all my compressors.....but how does this little, hard working compressor get rid of moisture?? Is THAT why the solenoid is HOT??? SHOULD the solenoid be hot to the touch even after I disconnected the compressor? How do I clean up the glass/solenoid after I remove it from the compressor??
I had a call into James at FT, and he said I have a leak in either the leveling system or the bladder. I am just following recommendations. Thanks, everyone

Re: compressor "cycling" every two minutes

Reply #20 – December 05, 2017, 08:19:15 pm

Glenn, there should be very little moisture coming out when it purges. Really not enough to worry about. If there is, you probably have other issues.

Re: compressor "cycling" every two minutes

Reply #21 – December 05, 2017, 08:28:38 pm

Quote from: GleamB – December 05, 2017, 08:12:19 pm

hdff .......THAT IS THE PART that I am talking about. It is VERY HOT to the touch, even though the compressor had been off for hours. I will take it apart, after running the compressor again, and see if there is a leak there. What I still don't understand is......if the glass part collects moisture, as with most air compressors, then WHERE DOES THE CONDENSATE GO???!!! I found a post written by Carol and Scot in 2013 that shows a picture of the solenoid, only HIS HAD A PETCOCK ON THE END OF THE SOLENOID. I can understand having to empty moisture from the compressor.....I have been doing that for years on all my compressors.....but how does this little, hard working compressor get rid of moisture?? Is THAT why the solenoid is HOT??? SHOULD the solenoid be hot to the touch even after I disconnected the compressor? How do I clean up the glass/solenoid after I remove it from the compressor??
I had a call into James at FT, and he said I have a leak in either the leveling system or the bladder. I am just following recommendations. Thanks, everyone

The solenoid is hot because the coil is energized. If compressor is disconnected and pressure falls, the pressure switch reads low pressure. This activates coil and compressor until pressure switch opens again at correct pressure and stops compressor and deactivates coil on solenoid valve. Because you have disabled compressor, coil will not drop out until pressure rises, and this will not happen because compressor is not running. The petcock is an add on and not necessary. I posted the part number in a previous post. I

Re: compressor "cycling" every two minutes

Reply #22 – December 05, 2017, 08:41:14 pm

HWH Solenoid Valve Rebuild

Here's something on the rebuilding of the solenoid, I did it but mine still didn't work, that's why I got a new one, plus found the metal piece in the bottom of bowl was cracked

Re: compressor "cycling" every two minutes

Reply #23 – December 05, 2017, 11:54:15 pm

hdff, did you have any trouble removing the valve from the glass? Did you replace the glass or clean it, at the same time you disassembled the valve to clean it ?? It is raining here for the next few days, and I can't open the joey bed without getting everything wet. Will have to wait a few days to try and clean it up. Hope I'm not hurting anything by having the compressor disconnected. That part gets pretty warm.
Thanks for the part number jcus.

Re: compressor "cycling" every two minutes

Reply #24 – December 06, 2017, 12:06:39 am

Quote from: GleamB – December 05, 2017, 11:54:15 pm

hdff, did you have any trouble removing the valve from the glass? Did you replace the glass or clean it, at the same time you disassembled the valve to clean it ?? It is raining here for the next few days, and I can't open the joey bed without getting everything wet. Will have to wait a few days to try and clean it up. Hope I'm not hurting anything by having the compressor disconnected. That part gets pretty warm.
Thanks for the part number jcus.

You should have just a plug type disconnect for the solenoid valve, just unplug it. If hardwired, just cut the wire.
The solenoid valve just dumps the water from the bowel assembly which removes some of the water. If you have to move the coach, you can without it, and if it is leaking, you can actually just remove it till you can fix it properly. You will need some 1/4 inch Home Depot fittings to do it, but can be done.
Foretravels are good coaches for workarounds, not always the right way, but the way that gets you to the house where you can do it correctly.

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