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HWH Max lift?
#1

My driveway is very steep. I managed to bring my coach to the house and got it into the driveway with lots of patience and blocking. Now that I'm much more familiar with the systems inside the coach does anyone know what the max over lift is using the HWH raise feature? From where my coach is currently sitting I've got the rear raised about 4 inches just using the HWH. This may not seem like much but the angle its parked at right now when in travel mode, the receiver hitch is touching the ground when aired up. So 4 inches is miles. My thought was not that i rebuilt the Aqua Hot i can just spin the exhaust pipe out and wont need as much clearance to get out of my driveway. I currently don't have the under coach pipe that goes through the roof. I will replace that when i move and have a more level driveway. The generator exhaust just needed an 8 foot 2x6 to lift the front end enough to clear. If i had 4 extra inches of height... I don't think ill need blocks at all.
I do know that the over lift will be limited to the total height of the bags. I was just wondering if anyone had a measurement, or a timeline of how long it can stay like that?

On a side note. Does anyone know where the leveling(ride height control valve) for the drivers seat is? Or should i just disconnect the air line?

Carl Little
1996 Coach 435 Detroit 60
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#2

May get two more inches out of the rear. Don’t pressurize the bags over 125 or you may get a surprise.

Depends on which seat you have. The innards are all under the seat cushion. Many of us have abandoned the overcomplicated and leak prone native system for a simple pneumatic paddle switch direct to the seat airbag.

Richard and Rhonda Entrekin
99 Newell, 512
Maverick Hybrid Toad
Inverness, FL (when we're home Cool )
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#3

Carl I just put a on off valve in line just turn it on till your happy then turn it off.

1999 45'  #504 "Magnolia"
Gravette, Arkansas
1996 40 XL Prevost Marathon 
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#4

(10-14-2024, 07:18 AM)Richard Wrote:  May get two more inches out of the rear. Don’t pressurize the bags over 125 or you may get a surprise.

Depends on which seat you have. The innards are all under the seat cushion. Many of us have abandoned the overcomplicated and leak prone native system for a simple pneumatic paddle switch direct to the seat airbag.

I would think that HWH system would have a max pressure switch that it wont exceed. I'll look through the book for it and see if its in there. I was an auto transporter for years and all our trucks had manual over lift systems. Those were just pressure solenoids that would inflate the bags to 120 and hold it there till we shut them off. Kind of like the older pump and dump solenoids.

A pneumatic paddle switch is the right solution,  That may actually be what the paddle switch on the side of the seat was supposed to be for. Or perhaps its for the swivel lock. Either way it doesn't work. I found the manual release for the swivel so perhaps ill just swap out the other paddle for a lift/ lower one.

Jack,
I like your idea as well. Simple and works.

Carl Little
1996 Coach 435 Detroit 60
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#5

Carl,

The hwh system is a little different than what you are imaging. With the engine running, the pressure is limited by the governor or the safety pop offs on the tank.

With engine off, the situation gets a bit more complex. The 120v compressor is normally controlled by a Square D well pump switch. Cut in about 70, cut out about 90. HOWEVER, if manually leveling or in AUTOLEVEL the HWH system sends a 12V signal to a relay box wired parallel to the Square D switch. The 12V signal closes relays which turn on the 120V compressor bypassing the pressure switch. A new Thomas compressor is capable over 150PSI. There is a device that looks like a pressure regulator on the line, but it is a fancy pressure relief. In my case, that device either failed or had been misadjusted. I left the system in autolevel and exploded a tag air bag. POW! There is NOT an electrical pressure switch in the HWH system to limit high pressure.

Richard and Rhonda Entrekin
99 Newell, 512
Maverick Hybrid Toad
Inverness, FL (when we're home Cool )
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#6

(10-14-2024, 11:41 AM)Richard Wrote:  Carl,

The hwh system is a little different than what you are imaging. With the engine running, the pressure is limited by the governor or the safety pop offs on the tank.

With engine off, the situation gets a bit more complex. The 120v compressor is normally controlled by a Square  D well pump switch. Cut in about 70, cut out about 90. HOWEVER, if manually leveling or in AUTOLEVEL the HWH system sends a 12V signal to a relay box wired parallel to the Square D switch. The 12V signal closes relays which turn on the 120V compressor bypassing the pressure switch. A new Thomas compressor is capable over 150PSI. There is a device that looks like a pressure regulator on the line, but it is a fancy pressure relief. In my case, that device either failed or had been misadjusted. I left the system in autolevel and exploded a tag air bag. POW! There is NOT an electrical pressure switch in the HWH system to limit high pressure.

You are correct. Their is no pressure switch for the tag axle. the steers and drives should have them though. In the manual i linked below it should be on page 10. Unless I'm not reading that correctly.
  I'm not fond of airbags blowing up in my face either. I've done it more than once.


Attached Files
.pdf HWH System.pdf Size: 334.86 KB  Downloads: 14

Carl Little
1996 Coach 435 Detroit 60
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#7

Yes, there are pressure switches on the six pack manifold. But they are LOW pressure switches intended to prevent lowering the coach all the way to its suspension limit on any one corner and thereby creating the potential for big frame twist.

They are failure prone and also NO switches. When they fail you should get the LEVEL warning light on the console. Newell service solution is to unplug them.

I am REALLY happy that you are reading that manual. It explains so much about the coach. You will have to tell me if I pass the test.

Richard and Rhonda Entrekin
99 Newell, 512
Maverick Hybrid Toad
Inverness, FL (when we're home Cool )
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#8

I like manuals. They answer just about every question one could have. I've downloaded and printed just about all of them i could think of for my coaches systems. I haven't found one for the ADS speakers or the electric blinds. Is there a section on here to upload manuals? Im more than happy to upload all the ones I've got.

Carl Little
1996 Coach 435 Detroit 60
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#9

Yes. Understand documentation

Tom

2002 45'8" Newell Coach 608  Series 60 DDEC4/Allison World 6 Speed HD4000MH

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