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HWH not dumping

The front left set of bags is not dumping properly.  It will dump to a certain point and then it acts like there is no more air in the bags to be dumped.  All of the other corners are setting on the tires but the front left is a few inches up off the tires.  I noticed the problem because our auto leveling was not acting right as it would try dropping the front and then begin to list to the right side.

Both of the front lowering solenoids have 12v when the respective control panel button is pushed.  Both seem to be working but the right side solenoid is exhausting significantly more air than the left side.  I unplugged the power wire one at a time and had Hannah operate the buttons.  The right side would really dump the air but the left was more like a slow leak than a dump.

We had a new manifold and all new solenoids installed in January.  Could there be some junk in the one solenoid that is not allowing it to open completely?  Up works fine and down seems to as well but at vastly different rates.

Thanks,
Tyler
Hannah and Tyler Phillips
1993 U280 Grand Villa AKA Pearl
Basement Air
Cummins 6CT8.3
Build Number 4196

Re: HWH not dumping

Reply #1 –
Is your coach sitting on a level pad, or is the ground under one front corner lower than under the other?  If the air bags on one front corner are completely empty, but the other side still has some air pressure, the HWH brain will inhibit the dump solenoid on that side.  This is to keep the front of the coach from "twisting" and causing damage to your windshield glass.

OR, a possible partially plugged exhaust port on the front 6-pack manifold?  Do you have Mud Dauber wasps in the neighborhood?

OR, like you supposed, a partially plugged "lower" solenoid caused by junk in the solenoid valve.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: HWH not dumping

Reply #2 –
Quote from: Chuck & Jeannie –
Is your coach sitting on a level pad, or is the ground under one front corner lower than under the other?  If the air bags on one front corner are completely empty, but the other side still has some air pressure, the HWH brain will inhibit the dump solenoid on that side.  This is to keep the front of the coach from "twisting" and causing damage to your windshield glass.

OR, a possible partially plugged exhaust port on the front 6-pack manifold?  Do you have Mud Dauber wasps in the neighborhood?

OR, like you supposed, a partially plugged "lower" solenoid caused by junk in the solenoid valve.
Chuck, you was right on with the mud dauber nest.  I pulled the solenoid and it was full of mud.  Got it all cleaned out and it's back to working like it should be.

Parker makes a NPT vent plug that will thread into the exhaust ports of the manifold, I might pick a couple up and put them in so we don't have that problem anymore. 

Thanks Chuck
Hannah and Tyler Phillips
1993 U280 Grand Villa AKA Pearl
Basement Air
Cummins 6CT8.3
Build Number 4196

Re: HWH not dumping

Reply #3 –
Hmmmm...hard to tell from that photo, but I'm not sure that is from a mud dauber.  When they plug up the exhaust port on the 6-pack manifold, it is usually a brown mud plug right at the surface opening of the port.  When you dig the mud plug out it often contains the carcass of one or more dead bugs and a wasp larvae.

I don't want to cause you more concern, but the stuff in that solenoid valve looks more like white desiccant powder to me.  If I am correct (and I hope I'm wrong) then you may have the old residue from a failed air dryer filter cartridge circulating in your air system.  If it has gotten as far as the front 6-pack manifold, then it is basically everywhere in your air system.

I'd just keep a sharp eye on all your air system valves and watch for any anomalous behavior.  Check your air tank drain valves often to see if any whitish looking mud is expelled when you open them.  If you really do have a contaminated air system, the white powder could show up almost anywhere, and you will probably find similar appearing material if you disassemble a malfunctioning valve.

Good Luck!
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: HWH not dumping

Reply #4 –
As a further diagnostic tool, open the rear, then front air tank drains.  What comes out?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: HWH not dumping

Reply #5 –
Quote from: Chuck & Jeannie –
Hmmmm...hard to tell from that photo, but I'm not sure that is from a mud dauber.  When they plug up the exhaust port on the 6-pack manifold, it is usually a brown mud plug right at the surface opening of the port.  When you dig the mud plug out it often contains the carcass of one or more dead bugs and a wasp larvae.

I don't want to cause you more concern, but the stuff in that solenoid valve looks more like white desiccant powder to me.  If I am correct (and I hope I'm wrong) then you may have the old residue from a failed air dryer filter cartridge circulating in your air system.  If it has gotten as far as the front 6-pack manifold, then it is basically everywhere in your air system.

I'd just keep a sharp eye on all your air system valves and watch for any anomalous behavior.  Check your air tank drain valves often to see if any whitish looking mud is expelled when you open them.  If you really do have a contaminated air system, the white powder could show up almost anywhere, and you will probably find similar appearing material if you disassemble a malfunctioning valve.

Good Luck!
There was more mud in it but it fell out before I got the picture.  I think it was probably the beginning of a nest that didn't get finished.  We had the air dryer serviced when we were at MOT so I hope it's not that.  Honestly though it wouldn't surprise me if it was something like that haha.  It didn't appear to be powder and I haven't seen anything like you described anywhere else in the system but I will keep an eye out for it.

I will check some other places and open the front and rear tanks like Mr. Wolfe suggested. 

Thanks again for all the help!
Tyler
Hannah and Tyler Phillips
1993 U280 Grand Villa AKA Pearl
Basement Air
Cummins 6CT8.3
Build Number 4196

Re: HWH not dumping

Reply #6 –
We still have plenty of air, so I ran out and checked all three of the tanks and nothing but clean air came out. 
Hannah and Tyler Phillips
1993 U280 Grand Villa AKA Pearl
Basement Air
Cummins 6CT8.3
Build Number 4196