HWH Aux Air Compressor Will Not Stop Running

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HWH Aux Air Compressor Will Not Stop Running

June 17, 2017, 02:46:59 pm

The HWH aux air compressor would not stop running until I disconnected the 5A fuse. According to the Operator Manual the pump should not operate more than 4 to 6 minutes without rest for 30 minutes, otherwise the unit would suffer damage. When the pump was running I could hear an air hissing sound that I had not heard before. I located the air was escaping from a solenoid valve (see picture) located under one of the filter housings. Normally this valve will expel excess air when the pump shuts down. I am guessing that the pump will not shut down because air is escaping from this valve while the pump is operating?? Can I adjust this valve so it will not leak air or do I need to replace? Note the desiccant in the other filter is pink and needs service. Could this affect the valve? I had the desiccant replaced at FOT on 3/9/17. The motorhome was in humid East Texas until March 23; and placed in storage in a dry southwest climate on March 30. Seems strange the desiccant would change color so quickly.

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #1 – June 17, 2017, 03:09:13 pm

Quote from: WagonWheels – June 17, 2017, 02:46:59 pm

The HWH aux air compressor would not stop running until I disconnected the 5A fuse. According to the Operator Manual the pump should not operate more than 4 to 6 minutes without rest for 30 minutes, otherwise the unit would suffer damage. When the pump was running I could hear an air hissing sound that I had not heard before. I located the air was escaping from a solenoid valve (see picture) located under one of the filter housings. Normally this valve will expel excess air when the pump shuts down. I am guessing that the pump will not shut down because air is escaping from this valve while the pump is operating?? Can I adjust this valve so it will not leak air or do I need to replace?

Well-known problem. Replace valve, keep old one and rebuild it so you have a spare. IIRC you get corrosion from the moisture and/or debris in the valve and that allows it to leak. One of the plungers/springs from Encantotom's HWH kits plus some corrosion remover is what you need to rebuild.

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #2 – June 17, 2017, 03:29:27 pm

Do you know the part number, name of leaking solenoid valve. Source for purchase?

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #3 – June 17, 2017, 03:39:40 pm

Depending on how often the compressor runs when it is working properly (determined by how tight your aide system is), will determine how often you need to replace the desiccant. My compressor currently runs about 4 times a day and I need to replace the desiccant about every 10-14 days.

There are several excellent threads on buying and recycling desiccant. One by Michelle if I remember correctly.

Rich

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #4 – June 17, 2017, 03:42:58 pm

Quote from: WagonWheels – June 17, 2017, 03:29:27 pm

Do you know the part number, name of leaking solenoid valve. Source for purchase?

Not knowing your coach year (hint hint - signature time

and yes, I know there's no coach in my signature either - just in transition here ;-) )...

If you have a Thomas TA-4101-DC aux compressor, it's HWH part number RAP6354, N/O solenoid.

FOT or MOT will have them in stock, but at an uplift. If you can get through to HWH, you can order it from them cheaper, but sometimes they can be "challenging" to get ahold of.

Rebuild info here HWH Solenoid Valve Rebuild

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #5 – June 17, 2017, 03:46:33 pm

Quote from: Rich Bowman – June 17, 2017, 03:39:40 pm

There are several excellent threads on buying and recycling desiccant. One by Michelle if I remember correctly.

Desiccant option for the HWH system

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #6 – June 17, 2017, 03:55:36 pm

Quote from: Michelle – June 17, 2017, 03:42:58 pm

Rebuild info here HWH Solenoid Valve Rebuild

Don't want to derail this thread, but what's the story on the "iRV Blog"? Is this something new? Did I not get the memo?

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #7 – June 17, 2017, 03:58:33 pm

Quote from: Chuck & Jeannie – June 17, 2017, 03:55:36 pm

Don't want to derail this thread, but what's the story on the "iRV Blog"? Is this something new? Did I not get the memo?

No, it's been around a long time; merger of several old blogs and goes back to our original LD days. I just couldn't find the post on Foreforums quickly.

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #8 – June 17, 2017, 04:01:22 pm

Well, like I keep saying, I learn something new every time I visit here. First time I ever heard of it or saw a link to it.

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #9 – June 17, 2017, 04:17:27 pm

Better yet, I just learned Steve put this stuff in the forum Wiki (he's been busy

)

technical:hwh:common-qa [ForeForums Foretravel Motorcoach Wiki]

technical:hwh:dryer [ForeForums Foretravel Motorcoach Wiki]

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #10 – July 02, 2017, 10:18:34 am

I ordered the solenoid part from HWH and after cleaning up the two air/water filter bowls, installed the new solenoid. To my surprise the pump worked and I didn't hear any air leaks. Granted its hard to hear air leaks when the pump is running. I didn't have any soapy water since the coach is in a storage lot.

However, I discovered another air leak that keeps the aux air pump running. I cranked the engine to charge the battery and exercise the engine. The Driver Info System and dash air gages showed both air systems pumped up to ~ 120 lbs. I turned off the engine after about 8 minutes and in a short time the aux air compressor kicked on and would not stop until I disconnected it. I noticed the coach air pressure had dropped below 70 lbs, thus the aux air compressor. I then turned on the engine to pump up the air system and then shut down the engine and walked around the coach listening for air leaks. I found air hissing from the engine area (curb side); behind the tag wheel. On a recent trip (early June) I noticed when camped that aux air pump would run from time to time to keep the coach level. A few minutes after the pump quit running the coach air system would purge air in a noisy burst from the curb side near the rear tires. Never had experienced this happening before. Site we were camped in was almost level. Any ideas? Who would do this type of service? It's a long way from Calif. to FOT in Nacogdoches.

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #11 – July 02, 2017, 11:05:24 am

David,

Nothing "uniquely Foretravel" about the air system. So, anyone familiar with OTR truck air systems should be able to work in it.

You may have several problems. Sounds like you have a bad check valve allowing air from the tanks back to the air dryer.

May also have a defective valve in the air dryer-- how long since it has been replaced/major service?

After the check valve is changed/repaired, THEN check for other air system leaks. 110 to 70 in a few minutes indicates a LARGE leak. Again, may all be going out the drier, but you will want to confirm.

Lastly, both Caterpillar and Cummins recommend against starting the engine unless you can drive a minimum of 25 highway miles-- long enough for the oil, not just coolant to reach operating temperature. This is not possible except under load.

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #12 – July 02, 2017, 11:09:42 am

Quote from: WagonWheels – July 02, 2017, 10:18:34 am

I found air hissing from the engine area (curb side); behind the tag wheel.

Was it more central to the engine area, perhaps near the transmission? If so, look at the recent discussion of the retarder air solenoid.

Allison retarder air valve

Replacing transmission retarder valve (split from What did you do to your coach)

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #13 – July 02, 2017, 11:58:22 am

I would like to chime in with a similar question. Our 97 has no slides. Been over the air system really close with soap. All the usual suspects. Step valves, everything that has air fittings.Air in system drops at normal rate, based on FT owner manual. Coach stays level for weeks, so no leaks at bags or level system.
I found the compressor running normal when the raised button is activated, but the gauges stay at the same air pressure, coach doesn't raise.
I pulled the compressor out to bench test it. Installed a gauge at the output. Found the 'T' split (probably froze) and the purge solenoid at the bottom of the water trap bottle leaking, repaired those. Turned in on, went to 115-120 lbs, and shut off. Check valve is OK. Reinstalled it in the coach. Still does the same thing. Runs, but coach doesn't raise. Even if I hold the button for 5 minutes.Coach does raise with full air.I can fill the tanks with my home compressor, everything works fine.
Chris

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #14 – July 02, 2017, 01:17:36 pm

Chris,

Do you have a air system diagram for your coach? It is almost essential for trouble-shooting this kind of question.

On my coach, the aux compressor output goes to two 4-way connectors, one each on the "front" and the "rear" tanks. It ties in downstream of the protection valve on each tank. From there the pressure goes directly to the "rear" HWH manifold, and through a 60psi pressure regulator to the "front" HWH manifold.

If your air system is plumbed like mine, and your protection valves are working properly, the aux compressor output cannot reach the air tanks. That is why you will not see any indication of pressure increase on your dash air gauges when the compressor is running.

If your aux pump is running and putting out pressure (you have already verified this with a pressure gauge at the pump outlet), and the pressure is not reaching the air bags (lifting the coach), then you probably have a leak in a air hose somewhere between the aux compressor and one (or both) of the HWH manifolds.

At least that's my armchair guess.

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #15 – July 02, 2017, 01:25:51 pm

Replace your RV1 valve. That's the valve Chuck's referring to.

277215 BENDIX RV-1 PRESSURE REDUCING VALVE 277215N | eBay

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #16 – July 02, 2017, 01:29:09 pm

Quote from: gracerace – July 02, 2017, 11:58:22 am

Still does the same thing. Runs, but coach doesn't raise. Even if I hold the button for 5 minutes.Coach does raise with full air.I can fill the tanks with my home compressor, everything works fine.

Chris,
Along with what Chuck has just posted Here is a question and a thought that goes along with his thoughts.

This leads me to believe that you are saying the compressor is running the whole time you have the raise button pushed. If this is the case look for a split hose from the little compressor to where it ties into the HWH system. The place that is most suspect will be where the line comes out of the cable tunnel. I have seen this line kinked just as it is trying to make the turn out of the tunnel causing the hose to split at that point. It will tale two people to check this area as one will need to push the raise button while the other is looking/listening for leaks at this hid point.

Pamela & Mike

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #17 – July 02, 2017, 06:59:14 pm

3/6/17: Had FOT install air dryer mod kit (DQ6026)
3/6/17: Complaint - coach will list to one side after storing it for a little while. Check for leaks. FOT checked all air fittings finding one leak at rear manifold. Replaced HWH Air Active Air Raise Solenoid 3/32 orifice (RAP1940)

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #18 – July 02, 2017, 09:37:46 pm

Quote from: Pamela & Mike – July 02, 2017, 01:29:09 pm

Chris,
Along with what Chuck has just posted Here is a question and a thought that goes along with his thoughts.

This leads me to believe that you are saying the compressor is running the whole time you have the raise button pushed. If this is the case look for a split hose from the little compressor to where it ties into the HWH system. The place that is most suspect will be where the line comes out of the cable tunnel. I have seen this line kinked just as it is trying to make the turn out of the tunnel causing the hose to split at that point. It will tale two people to check this area as one will need to push the raise button while the other is looking/listening for leaks at this hid point.

Pamela & Mike

Thanks Chuck and Mike.
I do have all the diagrams.I saw where the compressor goes in the diagrams.It was daunting to look at. I was thinking along the split or pinch in the line area.
Just thought maybe someone had a similar issue, and could narrow it down a bit. Which you guys did.
Cheers. Will follow up later when I find it.

Re: HWH Aux Air Compressor Will Not Stop Running

Reply #19 – July 02, 2017, 11:12:23 pm

Quote from: Twig – July 02, 2017, 01:25:51 pm

Replace your RV1 valve. That's the valve Chuck's referring to.

277215 BENDIX RV-1 PRESSURE REDUCING VALVE 277215N | eBay

Thanks. Have about 4 good ones, from when I was a FT tech. Replaced gauges and step solenoids, so we just replaced it all.

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