Skip to main content ↑ ↓
Topic: Air system over view (Read 886 times) previous topic - next topic

Air system over view

I would like to get a clear understanding of the air system throughout the coach. My on board compressor does not seem to be operational (pic). I am sure somewhere here there is a diagram and explanation of the system as a whole.

Thanks, Phil
1999 U320
Mount Dora Fl

Re: Air system over view

Reply #1 –
Quote from: philtravel –
I would like to get a clear understanding of the air system throughout the coach. My on board compressor does not seem to be operational (pic). I am sure somewhere here there is a diagram and explanation of the system as a whole.

Thanks, Phil

Phil,

This is for our U300 but should be about the same.

Do a search for a couple of good explanations from previous posts.

Best,

Pierce

Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Air system over view

Reply #2 –
Thanks Pierce, I now realize I should have gone and looked in my manual.

Anyone know where or if there is a control switch for the 12 volt compressor on my 1999 U320. Is it normally left on and controlled by the pressure switch?
1999 U320
Mount Dora Fl

Re: Air system over view

Reply #3 –
Phil,

Here is a diagram on how to check your 12 compressor for operation.

I have the complete HWH repair manual for the 600 series so let me know if you need more info.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Air system over view

Reply #4 –
Thanks Pierce I will go and try and sort it out.
1999 U320
Mount Dora Fl

Re: Air system over view

Reply #5 –
So I am not getting 12v from the control box. I checked the wire marked 9700 as on the schematic. Where is the control box? Is this the leveling control? I jumped the relay and the compressor ran.
1999 U320
Mount Dora Fl

Re: Air system over view

Reply #6 –
So, if there is not a control switch on my unit I would like to add one even if it is at the compressor so I can build pressure so I am not so noisy when we are leaving a site when getting ready to leave. Has any one done this?
1999 U320
Mount Dora Fl

Re: Air system over view

Reply #7 –
Sounds like a good idea. Waiting for air pressure at high altitudes/cold weather does not make many friends in campgrounds. On the other hand, it does control the mosquito population.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Air system over view

Reply #8 –
Is the Aux air compressor only for the systems in the leveling and air bag side?  After the six packs?

So the main chassis air won't be built up normally?
My coach until recently would drop the main air tanks to zero after a few days parked. Suspension never moves. 
Mechanic buddy found all the leaks it seems in the compressor part of the system.

Now both gauges stop a 60psi.  Was it a stuck valve?

I would think the little compressor would be hard put to fill the coach side to 130psi.  The engine air compressor must have many times more volume?

A separate  bigger 110 volt compressor plugged into the air system might do the chassis air up faster?

"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Air system over view

Reply #9 –
Anyone have a picture of the control box? I am not sure what I am looking for.
1999 U320
Mount Dora Fl

Re: Air system over view

Reply #10 –
Quote from: Caflashbob –
Is the Aux air compressor only for the systems in the leveling and air bag side?  After the six packs?
So the main chassis air won't be built up normally?

I would think the little compressor would be hard put to fill the coach side to 130psi.  The engine air compressor must have many times more volume?
A separate  bigger 110 volt compressor plugged into the air system might do the chassis air up faster?
On the older coaches this is correct. On the newer coaches like my 2003 you can air up from the larger Aux Compressor.

Quote
My coach until recently would drop the main air tanks to zero after a few days parked. Suspension never moves. 
Mechanic buddy found all the leaks it seems in the compressor part of the system.
Now both gauges stop a 60psi.  Was it a stuck valve?
There are "Protection Valves" on Front and Rear tanks that stop at 60psi.

The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Air system over view

Reply #11 –
Caflashbob:

The stop at 60 psi is probably due to the protection valves which are on both the front air tank and the rear air tank. These protection valves will shut off air supply to non-braking devices (step, sliding floor, horn, air bags) to retain air for stopping if a drastic air leak suddenly developes when driving down the road. They will do the same thing when you are parked and provide a clue to where an air leak may be.

The small 12volt air compressor is connected through one way valves such that they will provide air to suspension air bags or slide air tubes  without filling the front/rear air tanks. This compressor is intended to keep your coach level when parked and not for filling the air tanks.

I installed a quick connector on mine so that I can attach a 120v air compressor or use the 12volt compressor as an air supply. I have also installed schrader valves on all suspension air bags so I can fill them from any air source, however, I would use caution when filling air tanks from an external source because the air must be dried. Moist air will cause damage to the air brakes and valves.
Wyatt
96 U320 40 WTFE, build 4943
84 Toyota Supra towd
2015 Jeep Wrangler towd
Victoria, BC, Canada

Re: Air system over view

Reply #12 –
Quote from: P. Wyatt Sabourin –
Caflashbob:

The stop at 60 psi is probably due to the protection valves which are on both the front air tank and the rear air tank. These protection valves will shut off air supply to non-braking devices (step, sliding floor, horn, air bags) to retain air for stopping if a drastic air leak suddenly developes when driving down the road. They will do the same thing when you are parked and provide a clue to where an air leak may be.

The small 12volt air compressor is connected through one way valves such that they will provide air to suspension air bags or slide air tubes  without filling the front/rear air tanks. This compressor is intended to keep your coach level when parked and not for filling the air tanks.

I installed a quick connector on mine so that I can attach a 120v air compressor or use the 12volt compressor as an air supply. I have also installed schrader valves on all suspension air bags so I can fill them from any air source, however, I would use caution when filling air tanks from an external source because the air must be dried. Moist air will cause damage to the air brakes and valves.

Thanks.  The multiple failure mode was/is in effect on my project coach.  The main chassis governor valve was sticking and had low pressure when it worked.  So the chassis continued to drop as the protector valves until now were not working.  Finally the spring brakes would stop the coach. Governor  I fixed the other fixed itself?  Have to ask my tech buddy if he messed with the safety valves.  Funny to fix itself after my 7,000 miles....coach has 108k on the speedo now.

Bob
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Air system over view

Reply #13 –
The compressor on your coach is only for the level system. In order to check it, dump the air from the tanks and then turn on the level system and hit raise, you should hear the compressor. You might have to have someone outside by the bay to hear the compressor
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Air system over view

Reply #14 –
Thanks Red Tractor I was thinking about it last night and realized I probably needed to activate the level system. Here at home when I park it is level so I come in and dump so the system was not on. 
1999 U320
Mount Dora Fl