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Topic: Auxiliary Compressor and Slides (Read 707 times) previous topic - next topic

Auxiliary Compressor and Slides

We went to bring in the slide this morning on our 2002 U270 and when we turned to switch, the bladder failed to deflate.  I could here a hiss in the bay, so I assume the HWH bladder process is trying to deflate the bladder.  Hit the HWH reset button and retried, but no joy.  It then occurred to me that the onboard auxiliary compressor hasn't run in a couple weeks (usually runs with self-level every day or 2).  I checked the fuse and can here it click when reinserting it so it is getting DC power.

We turned on the engine and aired up and after that was able to deflate the bladder and bring in the slide, and the bladder re-inflated.

I thought I read somewhere that the onboard compressor is necessary for the slide bladder to inflate and deflate, but that doesn't seem to be the case.  Can someone confirm one way or the other?

Troubleshooting:  Suggestions for next steps?  I assume I need to see if the air pressure sensor switch is sticking.  Anything else to check.

Finally, there us an AIR switch next to the HWH reset button on the console.  Normally it is always off.  When I turn it on it lights up but no effect I can see on the compressor.  What exactly is the purpose of this switch?

Thanks all
Joe Phebus and Jaime Trujillo
2002 U270 3410  Build: 5953 Motorcader # 18595
2100 W Solar, 600 AH Battleborn Batteries,  Victron Multi-Plus II 3000 Inverter, Cerbo GX, & MPPT Chargers
1992 Geo Tracker

Re: Auxiliary Compressor and Slides

Reply #1 –
You air system should be close to mine.  If the check valves are working then engine produced air will not deflate the bladder.  That air comes from the HWH tank.  Look for drawing B2193.

Check pressure switch, mine was sticking, replaced it.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Auxiliary Compressor and Slides

Reply #2 –
Quote from: Roger & Susan in Home2 –
You air system should be close to mine.  If the check valves are working then engine produced air will not deflate the bladder.  That air comes from the HWH tank.  Look for drawing B2193.

Check pressure switch, mine was sticking, replaced it.

Thanks, Roger

Seems similar, although mine seems to be connected to a wet tank.  I wonder if there's a check valve failure that might be allowing air from the wet tank back to the compressor S/O air tank.  That might explain why the bladder deflated after we fired up the engine, do you think?  As an amateur looking at the diagram, it would seem there should be no backflow from the wet tank.

I'll check the pressure valve in the morning.    After we turned the slide control on, there was air coming out of the Vacuum Gen block for the slide before firing up the engine and then much more forcefully after.  Is this normal, or maybe a leak there?  I hadn't  notice whether or not it discharged air when the slide switch was the on position in the past.

 
Joe Phebus and Jaime Trujillo
2002 U270 3410  Build: 5953 Motorcader # 18595
2100 W Solar, 600 AH Battleborn Batteries,  Victron Multi-Plus II 3000 Inverter, Cerbo GX, & MPPT Chargers
1992 Geo Tracker

Re: Auxiliary Compressor and Slides

Reply #3 –
Quote from: Joe Phebus –

Finally, there us an AIR switch next to the HWH reset button on the console.  Normally it is always off.  When I turn it on it lights up but no effect I can see on the compressor.  What exactly is the purpose of this switch?


The Air switch by the driver's elbow in a 2002 and newer operates a solenoid valve that links the HWH aux compressor plumbing to the main coach brake/leveling tanks.

It was added/intended to be a "campground courtesy" so you could start airing up the coach without starting the main engine (and being noisy).

It shouldn't be left on, and should only be used if absolutely necessary.

They have been known to leak (as well as the check valve in that line).  To test for leak through, with the AIR switch off, turn the ignition key to power the Driver Info Center, but don't start the coach.  Note A&B tank pressures.  When the aux compressor runs to top off the slide bladder tank, watch the A&B tank pressures.  If they increase, the AIR switch solenoid valve is leaking.

I don't know of an easy way to test the check valve.  If it has failed AND the AIR switch solenoid is leaking, it would push A&B tank air into the HWH system.

The latter makes me wonder if the vacuum generator airflow increase you noted with the engine running could be that scenario...
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Auxiliary Compressor and Slides

Reply #4 –
If starting the engine increases the air low theough the bladder manifold then it is likely there is a check valve issue. The check valve in line 57 may be accessible in the basement, on mine it is in-line.  Maybe 1.25x2". 
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Auxiliary Compressor and Slides

Reply #5 –
Michelle and Rodger, thanks for sharing your knowledge and experience.  As it turned out, the relay and water trap solenoid on the auxiliary compressor failed.  The compressor wasn't coming on because the the auxiliary air tank relay (with a PC board) .  After replacing that, the compressor came on but the water trap solenoid stayed open so the system was unable to build pressure.  We ended up plugging it as a stop-gap until I can get a new one from HWH (unless someone know of another source).  I'm going to call HWH on Monday and see order a new water trap solenoid one and spares for both parts. 

It seems odd that both parts would fail at the same time. The water trap solenoid was responding to a charge, bit not closing the valve when current was applied, so likely the valve itself.  Best I can figure is the water trap valve failed causing the compressor to run continuously and that, in turn burned out the relay switch.

Slide seal bladder is deflating and inflating normally now.  I'm just going leave the air switch off and not try to figure that out for now.  Maybe a trip to HWH in the spring for a full system checkup.   

Attached is a picture of the 2 failed parts.

     
Joe Phebus and Jaime Trujillo
2002 U270 3410  Build: 5953 Motorcader # 18595
2100 W Solar, 600 AH Battleborn Batteries,  Victron Multi-Plus II 3000 Inverter, Cerbo GX, & MPPT Chargers
1992 Geo Tracker

Re: Auxiliary Compressor and Slides

Reply #6 –
Quote from: Joe Phebus –
Michelle and Rodger, thanks for sharing your knowledge and experience.  As it turned out, the relay and water trap solenoid on the auxiliary compressor failed.  The compressor wasn't coming on because the the auxiliary air tank relay (with a PC board) .  After replacing that, the compressor came on but the water trap solenoid stayed open so the system was unable to build pressure.  We ended up plugging it as a stop-gap until I can get a new one from HWH (unless someone know of another source).  I'm going to call HWH on Monday and see order a new water trap solenoid one and spares for both parts. 

It seems odd that both parts would fail at the same time. The water trap solenoid was responding to a charge, bit not closing the valve when current was applied, so likely the valve itself.  Best I can figure is the water trap valve failed causing the compressor to run continuously and that, in turn burned out the relay switch.     

The NO solenoid valve for the condensate bowl and the clear bowl itself are common failures.

#1 there's a rapid temperature change when the compressor shuts off and the condensate blows off.  The bowl develops thermal cracking around the "port" at the bottom where that valve screw in.  (we have also seen catastrophic failure of that bowl as well).

#2 stuff blows past that valve seat when it opens and can foul the seat so that it doesn't seal all the way.

If you have the same setup our '03 had, the condensate bowl is available from a variety of suppliers.  Here's info with p/n's

HWH Filters and Bowls

You can rebuild the old NO solenoid valve and keep it as a spare.  I believe the plunger kits Tom sells for the HWH 6-pack solenoids may work/fit for this.

HWH Solenoid Valve Rebuild
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Auxiliary Compressor and Slides

Reply #7 –
Joe, this is the wiring digram from HWH with the dash switch and the solenoid valve to send air to the Wet tank.

The water trap solenoid closes when the pressure switch closes or when the HWH System calls for air or when the dash switch is closed. The Essex relay is a tough one, might have been some other wiring issue.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Auxiliary Compressor and Slides

Reply #8 –
Quote from: Roger & Susan in Home2 –
Joe, this is the wiring digram from HWH with the dash switch and the solenoid valve to send air to the Wet tank.

The water trap solenoid closes when the pressure switch closes or when the HWH System calls for air or when the dash switch is closed. The Essex relay is a tough one, might have been some other wiring issue.

Thanks,  It is strange.  I was thinking maybe I have it backwards and the Essex relay failed first.  In that scenario, maybe the water trap solenoid flipped to closed and stayed closed (and powered) waiting for air via the compressor and overheated causing the solenoid to overheat and fail.

Joe
Joe Phebus and Jaime Trujillo
2002 U270 3410  Build: 5953 Motorcader # 18595
2100 W Solar, 600 AH Battleborn Batteries,  Victron Multi-Plus II 3000 Inverter, Cerbo GX, & MPPT Chargers
1992 Geo Tracker

Re: Auxiliary Compressor and Slides

Reply #9 –
Quote from: Michelle –
The NO solenoid valve for the condensate bowl and the clear bowl itself are common failures.

#1 there's a rapid temperature change when the compressor shuts off and the condensate blows off.  The bowl develops thermal cracking around the "port" at the bottom where that valve screw in.  (we have also seen catastrophic failure of that bowl as well).

#2 stuff blows past that valve seat when it opens and can foul the seat so that it doesn't seal all the way.

If you have the same setup our '03 had, the condensate bowl is available from a variety of suppliers.  Here's info with p/n's

HWH Filters and Bowls

You can rebuild the old NO solenoid valve and keep it as a spare.  I believe the plunger kits Tom sells for the HWH 6-pack solenoids may work/fit for this.

HWH Solenoid Valve Rebuild

Thanks, Michelle.  Reading this, I'm thinking plugging the water trap bowel as a temporary fix might not be ideal.  Could possibly blow it up, no? 

 I'm going to order the bowl and (hopefully) a new NO solenoid from Foretravel ASAP.  I might give rebuilding the solenoid a shot in the meantime.

 
Joe Phebus and Jaime Trujillo
2002 U270 3410  Build: 5953 Motorcader # 18595
2100 W Solar, 600 AH Battleborn Batteries,  Victron Multi-Plus II 3000 Inverter, Cerbo GX, & MPPT Chargers
1992 Geo Tracker