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Topic: Max governor PSI (Read 799 times) previous topic - next topic

Max governor PSI

So thanks to my new found leaks, I'm unable to build enough pressure to get one corner of the coach high enough to insert safety stands. I'm only off by about 2 inches so I think the solve here is to temporarily turn up the pressure at the governor to compensate for the leak-down. Then I can slide under and fix those leaks.

My question is, how high is too high? 150psi? 200?

The alternative is to have a couple more safety stands cut at a shorter length but that's a bigger hassle.
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.

Re: Max governor PSI

Reply #1 –
Your maximum air system pressure should never exceed 150 psi.  You should have a safety pressure release valve on your wet tank which should open at approximately 150 psi.  If it opens it will be very loud.

Don't ask how I know.

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: Max governor PSI

Reply #2 –
I set mine @ 150psi.
Tim Dianics
Pam Sapienza
Vader PupZilla Labrador Canine Beast (AKA Pup)
Columbia, MO
1996 U320 4000
2021 Jeep Gladiator, Diesel

Re: Max governor PSI

Reply #3 –
The governor pressure won't go above the front air bag regulator set pressure which is around 70 psi. I believe.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Max governor PSI

Reply #4 –
Quote from: craneman –
The governor pressure won't go above the front air bag regulator set pressure which is around 70 psi. I believe.
The leaks are before the front tank and why I can't get one of the front bags all the way up so I don't think I'm hitting the top end of that regulator.
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.

Re: Max governor PSI

Reply #5 –
You need volume to compensate for the leaks not pressure. Do you have a 120 volt air compressor you could put in the air fitting on the coach? I have a male to male fitting for emergencies like you are having.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Max governor PSI

Reply #6 –
Quote from: TGordon –
I set mine @ 150psi.
So you are saying your D2 governor is set to cut out the air compressor at 150psi?  Your dash air gauges both read 150psi when your air dryer purges?

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: Max governor PSI

Reply #7 –
Quote from: craneman –
You need volume to compensate for the leaks not pressure. Do you have a 120 volt air compressor you could put in the air fitting on the coach? I have a male to male fitting for emergencies like you are having.
I don't have the fitting. I've been meaning to make a connector with inline air dryer for a compressor but haven't yet. Maybe it's time
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.

Re: Max governor PSI

Reply #8 –
Quote from: craneman –
The governor pressure won't go above the front air bag regulator set pressure which is around 70 psi. I believe.
I think Elliott is talking about his D2 governor...unless I completely misunderstood his question.

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: Max governor PSI

Reply #10 –
If your air compressor is cutting out at 130psi that is plenty of pressure to raise both ends of your coach.

If it is a front corner that will not reach full height, you could try raising the setting on the front 6-pack air pressure regulator.  Normal setting is 60-65psi.  Raising it to 70-80psi won't hurt a thing.

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: Max governor PSI

Reply #11 –
Quote from: Chuck & Jeannie –
I think Elliott is talking about his D2 governor...unless I completely misunderstood his question.

That is what I assumed also. Raising the pressure won't compensate for the cfm loss due to the air leaks very much he needs more volume or cfm.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Max governor PSI

Reply #12 –
Quote from: Chuck & Jeannie –
So you are saying your D2 governor is set to cut out the air compressor at 150psi?  Your dash air gauges both read 150psi when your air dryer purges?
Yes.
Easier to inflate tires

Tim Dianics
Pam Sapienza
Vader PupZilla Labrador Canine Beast (AKA Pup)
Columbia, MO
1996 U320 4000
2021 Jeep Gladiator, Diesel

Re: Max governor PSI

Reply #13 –
Elliott,

Just to be clear - is it a front corner that will not go up high enough?

Are you able follow the procedure below all the way through the 4 steps, or are your air leaks preventing you from doing so?

1.  Running the engine with coach at normal ride height, let air pressure build up until the dryer purges (compressor cuts out).
2.  Hold down the RAISE button.  The air pressure on your dash gauges should drop down below cut-in pressure as the coach goes up.
3.  Continue holding the RAISE button until the air compressor cuts in and air pressure comes back up to cut out pressure.
4.  When compressor cuts out and dryer purges, the coach is as high as it is going to go.  Turn ignition switch off, THEN release RAISE  button.

At this point, if all 4 corners of your coach are not high enough to insert your safety stands, then you have some other problem.  It is not lack of air pressure OR air volume (cfm) that is causing the problem.


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: Max governor PSI

Reply #14 –
Quote from: TGordon –
Yes
OK...  It's your coach, so DWMYH.

If you are going to run your air system at 150psi on a regular basis, I would recommend checking the safety pressure relief valve on your wet tank to ensure it is functioning properly.  If it is dirty or corroded it may not open at the designated pressure.  The opening pressure should be indicated on the valve body.

Safety relief valve wet tank


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: Max governor PSI

Reply #15 –
Quote from: Chuck & Jeannie –
OK...  It's your coach, so DWMYH.

If you are going to run your air system at 150psi on a regular basis, I would recommend checking the safety pressure relief valve on your wet tank to ensure it is functioning properly.  If it is dirty or corroded it may not open at the designated pressure.  The opening pressure should be indicated on the valve body.

Safety relief valve wet tank



Not to mention compressor life will be reduced being operated at its upper range. And this comes with the added fuel to run at higher pressures and extended run times.

Re: Max governor PSI

Reply #16 –
Quote from: Chuck & Jeannie –
Elliott,

Just to be clear - is it a front corner that will not go up high enough?

Are you able follow this procedure all the way through the 4 steps, or are your air leaks preventing you from doing so?

1.  Running the engine with coach at normal ride height, let air pressure build up until the dryer purges (compressor cuts out).
2.  Hold down the RAISE button.  The air pressure on your dash gauges should drop down below cut-in pressure as the coach goes up.
3.  Continue holding the RAISE button until the air compressor cuts in and air pressure comes back up to cut out pressure.
4.  When compressor cuts out and dryer purges, the coach is as high as it is going to go.  Turn ignition switch off, THEN release RAISE  button.

At this point, if all 4 corners of your coach are not high enough to insert your safety stands, then you have some other problem.  It is not lack of air pressure OR air volume (cfm) that is causing the problem.
It's my front right corner that won't go up high enough. The coach isn't perfectly level and this is the highest corner by just a little bit.

I follow that process to raise my coach normally and it works fine. Currently, when I hit RAISE all three corners go up and the forth doesn't quite make it to full height, regardless of how long I try. I don't THINK I've heard the dryer's purge valve when raising the coach but I do when in travel mode. Prior to it sitting for a couple months, I was raising it all the time without issue in this exact spot.

I'm going to get out there tonight after work and turn the governor up to 150psi and see if that does the trick
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.

Re: Max governor PSI

Reply #17 –
The reason I would wait for the compressor to cut out (Step #4) is to insure that the leveling system has full max system air pressure (120-130 psi) to work with.  ALSO, if the air compressor cuts out, it means the compressor is putting out more air volume than is being lost through your leaks.  In that case, the leaks are not preventing the coach from reaching full height.

The pressure to the front 6-pack during manual leveling or using the RAISE button is controlled by the 6-pack pressure regulator.  For most coaches, having this regulator set at 60-65 psi provides plenty of pressure to insure full air bag extension.  However, there have been cases when a member reported having difficulty with the front end raising, and increasing the setting on the regulator seemed to solve the problem.

It wouldn't hurt a thing to try raising the regulator setting to 70 or 80 psi and see what happens.

See threads below for some old discussions on "What the heck is the purpose of that front pressure regulator?"

Air Suspension Pressure regulator

Six pack left front not raising

air leaking, what is this?

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: Max governor PSI

Reply #18 –
Quote from: Chuck & Jeannie –
It wouldn't hurt a thing to try raising the regulator setting to 70 or 80 psi and see what happens.

The front regulator is under the coach though, right?  :'(

1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.

Re: Max governor PSI

Reply #19 –
Quote from: Elliott –

I'm going to get out there tonight after work and turn the governor up to 150psi and see if that does the trick

That WILL NOT HELP.  That adjust tank pressure, not pressure to the front air bags.

Remember, only one ride height valve in front.

The two in the rear control left/right height.
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: Max governor PSI

Reply #20 –
Quote from: Elliott –
The front regulator is under the coach though, right?  :'(
Yes - under the front end, tucked up near the two air tanks.  Looks like a common regulator on shop air compressors.  Has a adjustment knob - gauge shows set pressure.
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: Max governor PSI

Reply #21 –
If you have a bottle jack you can raise the frame to insert safety supports.
1998 36' U295 Mechanical 8.3

Re: Max governor PSI

Reply #22 –
Quote from: wolfe10 –
That WILL NOT HELP.  That adjust tank pressure, not pressure to the front air bags.
My issue is that the leaks are after the rear tank and before the front tank. My hypothesis is that they're severe enough that the front tank isn't building enough pressure to get the front bags all the way up. I'm hoping increased pressure in the rear tank will translate to adequate pressure in the front tank..
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.

Re: Max governor PSI

Reply #23 –
Quote from: Elliott –
My issue is that the leaks are after the rear tank and before the front tank. My hypothesis is that they're severe enough that the front tank isn't building enough pressure to get the front bags all the way up. I'm hoping increased pressure in the rear tank will translate to adequate pressure in the front tank..
I don't know what you are calling your "rear" tank.  Do you mean the wet tank?

You don't have to guess what the pressure is in your front and rear brake tanks - just look at your dash gauges.

If your dash air gauge shows 120-130 psi in the front brake tank, then air system pressure is not your problem.

As mentioned above, the front 6-pack regulator will determine what pressure goes to the front air bags.

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: Max governor PSI

Reply #24 –
Quote from: Chuck & Jeannie –
I don't know what you are calling your "rear" tank.
Rear brake tank.

Pressure in both gauges reads at 120psi before I hit raise. Once I hit raise, they almost immediately drop to the cutoff around 75psi. Not sure if the front gauge ever gets back up to 120psi as I'm hitting "raise'.  That's something I'll check tonight.
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.