Compressor going on and off!

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Compressor going on and off!

August 20, 2019, 08:35:21 am

Well, it seems this is the month for little items to trouble shoot! We arrived at our new destination yesterday and set the coach up. A few minutes later, I heard the compressor kick on, but shut of in less than 10 seconds. Looked at the air gauges on the dash and both were at or near 70 lbs. About 5 minutes or less goes by and the compressor kicked on again. It did this all night long and still this doing this now!
I did have to raise the coach up several times coming out of and then back into a steep area to keep front or rear dragging. Could this be the issue with maybe a valve sticking? I believe this is the compressor for the slide bladder and the HWH system.

Normally, with coach sitting, the compressor might come on once or twice a day and the air gauges would then air up to approximately 110 lbs. It would bleed down over time, but very slowly.
Any ideas out there to stop this constant running of the compressor? Once you hear it, you hear it all night! UGH!
Would going back into travel mode again and raise the coach up and then dump the air work? Just thinking out loud!
Any help on this would be most appreciated. Thanks in advance!

Re: Compressor going on and off!

Reply #1 – August 20, 2019, 09:08:03 am

I don't have a slide so I don't know the effects on one but what I do after I park and level , I turn the HWH off , that stops compressor from coming on.. My air bags have no leaks so I stay level even with no noisy compressor.

Re: Compressor going on and off!

Reply #2 – August 20, 2019, 09:24:14 am

Quote from: Dub – August 20, 2019, 09:08:03 am

I don't have a slide so I don't know the effects on one but what I do after I park and level , I turn the HWH off , that stops compressor from coming on.. My air bags have no leaks so I stay level even with no noisy compressor.

Dub, yes, that would work, but I still want to figure out why it is doing what it is doing. We have a new bladder seal and all new air bags, so should be good to go there. Hoping someone out there has had this happen and can offer a solution to issue!

Re: Compressor going on and off!

Reply #3 – August 20, 2019, 09:37:54 am

You have an air leak somewhere.. Only way a "stuck" valve would be the issue is if one were stuck open... but you could hear that and I'm assuming you can't hear the leak..You know the drill on finding air leaks.. Myself I would do as I said until I got back home to my shop with a creeper and concrete floor. Maybe someone knows a "quicker fix", but my search for air leaks has never been quick.

Re: Compressor going on and off!

Reply #4 – August 20, 2019, 09:44:50 am

Won't hurt anything to go thru the process you mentioned but I have doubts stopping the leak doing so.

Re: Compressor going on and off!

Reply #5 – August 20, 2019, 11:57:08 am

Turned off the HWH and the compressor still ran. It would go from around 72 lbs down to 70 and then kick back on, so I pulled the 20 amp fuse that is located at the compressor and that stopped the compressor from coming on. After several hours, air tanks are still at same pressure as when I pulled the fuse, so there should be not be a valve leaking. Something is not allowing the compressor to pump air past a couple of pounds of air and shut off. I know there is a pressure regulator on the pump, but not sure if that is the issue.
Anybody else have an idea?
I agree Dub, a creeper and a concrete floor would be ideal to find leaks, but with the pressure not dropping, I don't think that is the issue!

Re: Compressor going on and off!

Reply #6 – August 20, 2019, 12:05:14 pm

You have a leak and the one way valve is stuck open. It should not pump up to 110 on the air gauges.

Re: Compressor going on and off!

Reply #7 – August 20, 2019, 12:26:07 pm

Joe, there are hundreds of places for leaks. Find your air system schematic and study it carefully. Unless to have failed check valves or your air system has been modified then the HWW compressor will do nothing (and should not) with the front and rear service tank pressures.

The compressor comes on when the pressure switch closes or the HWH box tells it to come on.there are check valves between the compressor and everything else. First place to look is near the compressor at the water separator bowl.

Add a switch to shut the compressor. Good place for this is between the pressure switch and the compressor start relay.

Re: Compressor going on and off!

Reply #8 – August 20, 2019, 03:12:41 pm

Quote from: John S – August 20, 2019, 12:05:14 pm

You have a leak and the one way valve is stuck open. It should not pump up to 110 on the air gauges.

John, is it possible the valves that raise the coach higher when in travel mode are stuck open? Would it then be possible if that is true, then I would not hear or find a leak, since the compressor won't go above that 72 lb pressure? Hope this makes sense!
Where we are set up, it is almost impossible to get under the coach, unless you are as slim as a pencil! lol

Re: Compressor going on and off!

Reply #9 – August 20, 2019, 03:19:17 pm

Quote from: Roger & Susan in Home2 – August 20, 2019, 12:26:07 pm

Joe, there are hundreds of places for leaks. Find your air system schematic and study it carefully. Unless to have failed check valves or your air system has been modified then the HWW compressor will do nothing (and should not) with the front and rear service tank pressures.

The compressor comes on when the pressure switch closes or the HWH box tells it to come on.there are check valves between the compressor and everything else. First place to look is near the compressor at the water separator bowl.

Add a switch to shut the compressor. Good place for this is between the pressure switch and the compressor start relay.

Roger, this is the small compressor in the large bay area with the slide tray. I have been in there and there are no leaks in or around that compressor. Compressor comes on at or about 70 lbs. and then shuts off at about 72 lbs. and the pop off valve releases pressure. I never had an issue until I raised the coach yesterday while in travel mode to clear the sloping ground. After that, the compressor started doing what it is doing now until I pulled the inline fuse by the compressor.
I may try moving to another site and try raising the coach in Travel Mode and then try to re level the coach and see what happens.
Will let you all know the results!

Re: Compressor going on and off!

Reply #10 – August 20, 2019, 04:47:16 pm

Here are some photos of our compressor and assembly of the system itself. I do have the ZipDee air awning, but it is disconnected and has never worked since I have owned the coach. Just a reference to maybe seeing extra air lines in the photos.
Photo #1 shows the collection glass and the pop off valve. There is no air coming out of that pop off when pulled now.
Photo #2 is the system itself.
Photo #3 shows the electric switch at the top with cover off and down below, you can see the cover for the fuse that I removed to stop the compressor from running.

Re: Compressor going on and off!

Reply #11 – August 20, 2019, 06:45:37 pm

Your pressure switch might be bad, these should go up to about 100 psi and shuts off the compressor. It closes at 20 psi below where it opens and turns the compressor on again. Find your air schematic drawing. Your coach is different from mine.

This schematic starts with build number 5871. I don't have any earlier ones.

Re: Compressor going on and off!

Reply #12 – August 20, 2019, 08:26:03 pm

Any chance the front end is raised to maximum height in your current location? That can will induce compressor run and then pop off to pop.

I had this happen one time. Driving the front tires up onto to 2" boards, then hitting re-level ended the problem.

Re: Compressor going on and off!

Reply #13 – August 20, 2019, 09:12:33 pm

Thanks Roger! Going to call James at FOT tomorrow and see what he suggests I screw up first! lol Just got back to the coach and looked at the two air gauges on the dash and they both have dropped down below 70 lbs. Top one was down to approx 62 and bottom gauge down to about 66. Of course I have had the compressor shut down with removal of the fuse.

Re: Compressor going on and off!

Reply #14 – August 20, 2019, 09:13:55 pm

Quote from: AC7880 – August 20, 2019, 08:26:03 pm

Any chance the front end is raised to maximum height in your current location? That can will induce compressor run and then pop off to pop.

I had this happen one time. Driving the front tires up onto to 2" boards, then hitting re-level ended the problem.

Dan, we are sitting low compared to some sites we have come into. lol

Re: Compressor going on and off!

Reply #15 – August 23, 2019, 06:07:49 pm

Update: Heard back from Ronnie at FOT and he did some checking and believes it is a valve that is stuck in the compressor itself. Suggested a light tap with the hammer and see if that rectifies the issue. On Monday, I am going to move the coach a few feet and raise and lower the coach, go to ride height and then level and see what happens. Will give an update after that.

Re: Compressor going on and off!

Reply #16 – September 06, 2019, 08:17:44 am

2nd Update: We move the other day to another RV park and still have an issue with the compressor in the bay.
We tried the tapping with the hammer (rubber) and no luck. Raised the coach and then lowered it, still the same. The day we left, the gauges on the dash were both at zero; so I then put the fuse back in that I had removed to stop the compressor from running and the compressor started right up and then kicked off. So, now it will not even put air into that small tank.
Decided to just see what happens further and started the coach and the air pressure came right up to 110/115, had brakes and deflated the slide seal to retract slide and all was good there. Brought the slide in and inflated the slide seal and again, all went well. So, down the road we went with no issues. Arrived at our next RV park and same thing. Once we shut the coach down, the small compressor would continued to run and shut off almost immediately.
Now I am wondering if we have a bad pressure switch, that is mounted in front of the compressor?
Calling Foretravel is not what it once was as before with James. I know that Ronnie is overwhelmed and doing his best, but it takes sometimes a full day before he can get back to someone with an issue. He and I both have been patient with this and we may have to live with this until we head back to Texas sometime in January. Just have to pull the fuse to stop the insane running of the compressor.

Re: Compressor going on and off!

Reply #17 – September 06, 2019, 09:11:16 am

Quote from: juicesqueezer – August 23, 2019, 06:07:49 pm

Heard back from Ronnie at FOT and he did some checking and believes it is a valve that is stuck in the compressor itself.

The only valves in my compressor are reed valves and they don't get stuck............. do they?

https://m.youtube.com/watch?v=8TI98cs85ew

Re: Compressor going on and off!

Reply #18 – September 06, 2019, 09:40:19 am

Juicesqueezers, do you have the air schematic?

The dash gauges show the front and rear brake tanks. Not the wet tank nor the slide seal tank. You need a gauge near the aux compressor to see whats happening at the s/o tank.

Re: Compressor going on and off!

Reply #19 – September 06, 2019, 09:51:56 am

Do you hear any air leaking near the compressor? Is the unloader solenoid leaking? Are there any cracks in the condensation bowl?

Do you hear any air leaking near the transmission?

KathyG posted while I was typing. Don't assume the compressor is trying to air up the main tanks (what does your air schematic look like?) If you do not have an "air tank" switch by the driver's elbow, then there is not a solenoid to do that and it does not put air into those tanks. If there is such a switch, it is possible the check valve or that solenoid is leaking through (we had that on our '03, but your '02 may not have that switch/solenoid/check valve scheme.)

Re: Compressor going on and off!

Reply #20 – September 06, 2019, 10:22:44 am

I feel a sense of frustration when I read threads like this. You have a simple problem: your air compressor runs at the wrong times or shuts off at the wrong time. It is cycling on/off rapidly. Why? It should be fairly easy to solve this problem with simple trouble shooting skills.

Step 1: What powers your air compressor? You know the answer to this because you have removed the fuse from the power wire.

Step 2: What tells the compressor to turn ON and OFF? You already know the answer to this because you have taken the cover off the pressure switch and pointed it out in your photos in Reply #10.

Step 3: If compressor is getting power (YES) but is turning ON or OFF at wrong times/pressures, what causes this? Answer: the pressure switch.

Step 4: How best to solve the problem? Answer: replace the pressure switch.

Discussion. The pressure switch is similar to the ones you will find on many air compressors, and also on water well pump controls. It employs a diaphragm to sense pressure, and spring loaded contact points that open and close to control power to a motor. One common problem is that the contact points will get dirty or eroded, and will not maintain the proper gap. Bad/dirty/corroded points can cause the switch to act erratically. If this IS the problem, you can "dress" the points (clean them up) with a "points file" and possibly restore proper operation...temporarily.

Another possible problem is the diaphragm can develop a tiny leak, causing erratic switch operation.

Another possible problem is the port into which the switch is installed can get plugged up with junk, causing erratic switch operation.

Occasionally, the switch operation can be restored by screwing the adjustment nut (on top of the big spring) in or out a bit. This nut is normally used to raise or lower the "kick in" and "kick out" settings on the switch. You could try messing with it to see if it makes any worthwhile change in your compressor's operation, but it probably won't help.

Once again: the SIMPLE solution is replace the pressure switch.

Once your compressor is back to operating at correct times and pressures, THEN you can go hunting for air leaks.

Re: Compressor going on and off!

Reply #21 – September 06, 2019, 10:32:22 am

Here is another thought about this rapid compressor cycling.

After looking at a generic air schematic for a 2000 (not the one for his exact coach) it shows a ball check valve just past the pressure switch. If this check valve has failed and is stuck closed it could be slowly bleeding through causing the pressure switch to see a need to come on. When the piping between the 2 is up to pressure the pressure switch is satisfied and shuts the compressor down.

Mike

Re: Compressor going on and off!

Reply #22 – September 06, 2019, 11:08:08 am

I had a similar issue a while back, and it ended up being an air bag leaking. We had been in some sites where the rear end had to raise to max height and I guess all the extra work found a weak spot in the left rear bag. Replaced air bag and no more cycling of the pump. Hope this helps and good luck.

Tracy

Re: Compressor going on and off!

Reply #23 – September 06, 2019, 02:07:17 pm

Quote from: Travelin' Man – September 06, 2019, 09:11:16 am

The only valves in my compressor are reed valves and they don't get stuck............. do they?

https://m.youtube.com/watch?v=8TI98cs85ew

It was just something Ronnie suggested to try! Not sure either!

Re: Compressor going on and off!

Reply #24 – September 06, 2019, 02:16:07 pm

Quote from: Michelle – September 06, 2019, 09:51:56 am

Do you hear any air leaking near the compressor? Is the unloader solenoid leaking? Are there any cracks in the condensation bowl?

Do you hear any air leaking near the transmission?

KathyG posted while I was typing. Don't assume the compressor is trying to air up the main tanks (what does your air schematic look like?) If you do not have an "air tank" switch by the driver's elbow, then there is not a solenoid to do that and it does not put air into those tanks. If there is such a switch, it is possible the check valve or that solenoid is leaking through (we had that on our '03, but your '02 may not have that switch/solenoid/check valve scheme.)

No switch there! I am missing the air schmatic for our coach. Have the full book, but those pages are missing. Not sure why!
When all was working well, when we would park and gauges slowly lost air over 8 hours, then the small compressor would come on, put 110/115 in the gauges on the dash and then shut off till air reached 70 +- lbs and then kick back on. This happened about once a day. When coach was back at MOT for air leaks and those major ones were repaired, the consensus was that the leak down over that time frame was acceptable and I had no issues with it either.
This all started when I raised the coach up to go over a rise in the road. I can not hear any air leaking, so leakage must be minute!

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