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Weird thing happening with air gauge
#1

I'm going to try and explain what is going on with my 120 air system. 

So over the course of 5 days or so , my 120 air gauge has registered zero twice but the pump is still running and not building air. Of course I cant open the door except when I release the emergency valve. As soon as  I start the engine the 120 air gauge immediately start working and the pump runs until it hit 122 psi then shuts off like normal.

I have found two medium leaks that are making the pump run every 16 18 minutes, I know I need to fix these but I didn't think it would cause the issue I am seeing Any ideas??

2005

home: Southern California
05 #746 quad slide 2000i, 
Steerable tag 
Detroit Diesel series 60 515 hp
Allison trans

Toad 2013 Avalanche Black Diamond edition 4 wheel drive
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#2

I had almost the same thing going on with my 120v air compressor but the opposite problem.  The 120 air system would gauge would go to zero without the compressor running.  Then on its own without doing anything with the system it would start working.  This happened on several occasions without any warning.  Suspecting the pressure switch I order a replacement....https://www.amazon.com/gp/product/B0078RSLAY/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1.  Changed it out and inspected the old one....the diaphragm was full of rust and crud.  Probably what was happening the rust and crud kept the switch from sensing low pressure that would turn the compressor on.

Having said this,  If your diagram has any crud and possibly a hole in it that gets uncovered in the low pressure ranges but covered up at the higher pressures could explain what you're seeing.

Steve

Steve & Doris Denton
45' Newell #525, Bath & Half
2014 Honda CRV Toad
Summerfield, FL
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#3

Thanks Steve,

Im still learning all this stuff is the pressure valve just above the pump on the left hand side?

home: Southern California
05 #746 quad slide 2000i, 
Steerable tag 
Detroit Diesel series 60 515 hp
Allison trans

Toad 2013 Avalanche Black Diamond edition 4 wheel drive
Reply
#4

Not sure about the 05 location mine is in the generator cooling fan bay R1...seems like I have seen a posting on this site where someone had a picture of their switch and it was located at the compressor.    My switch is a factory preset 80 to 100 psi switch.  Yours being a 120 psi cutout switch would be a different part # than the link I posted from Amazon.  If you get into changing it out all the appropriate safety precautions apply.

Steve & Doris Denton
45' Newell #525, Bath & Half
2014 Honda CRV Toad
Summerfield, FL
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#5

OK thanks, I think it's right near my seperator. I plan on call newell on Monday to see if they can figure it out.

home: Southern California
05 #746 quad slide 2000i, 
Steerable tag 
Detroit Diesel series 60 515 hp
Allison trans

Toad 2013 Avalanche Black Diamond edition 4 wheel drive
Reply
#6

Carthan,

This is my opinion so take it as so. But I think my comments are reasonably accurate. The bulk of the experience on this forum is with 2004 and earlier coaches. After that Newell made changes by going to multiplex systems, and using slightly different components in the air system. There are a handful of gurus with hands on experience with your vintage.

That being said, and keeping in mind that no two Newells are alike, it will be most helpful going forward to take pictures of the area or problem of interest so that we can see what you see. Otherwise we are commenting based on what we have seen, which may not be what you have. That’s kind of the neg side of the situation, the positive side is that Newell was a builder who used a slow progression of evolution in their systems, so it is fairly straightforward to trace the DNA back to something we recognize.

Let me illustrate. As late as 2004 Newell was equipping the coaches with one 120V aux compressor and one 12V aux compressor. There is a specific pneumatic piping setup that works with that setup. That combo uses the well pump switches of which we mention to control the on off of both compressors. By 2007, Newell had switched to a dual 120V compressor setup all driven by the Valid electronics. You are somewhere in between, and I personally do not have a clue as to your setup.

So let’s start by posting pictures of you air comp setup.

A SWAG is that someone used a pilot operated valve on the air compressor drain/pressure release instead of a direct acting valve. That valve requires air pressure and an electrical signal to close it. Without any pressure, it doesn’t close and the compressor output just dumps to atmosphere. This is just a WAG based on previous experience.

Richard and Rhonda Entrekin
99 Newell, 512
Maverick Hybrid Toad
Inverness, FL (when we're home Cool )
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#7

Richard, here is what my 2 pumps look like, I've found two leaks like the one below



[Image: 20200329_182442.jpg]

[Image: 20200329_182855.jpg]

[Image: 20200329_194127.jpg]

home: Southern California
05 #746 quad slide 2000i, 
Steerable tag 
Detroit Diesel series 60 515 hp
Allison trans

Toad 2013 Avalanche Black Diamond edition 4 wheel drive
Reply
#8

A ha. You have the dual 120V compressor setup as supplied by Valid. All the conversation about pump switches does not apply to you. Perhaps one of the guys with that setup can help, @"valento" @DK on the road


You will learn in chasing air leaks that those style fittings, called push on or push to connect, eventually start to leak like that. A lot of us replace it with a compression fitting when we fix it. Please always use DOT approved fittings when working on your air system. They are quite different than what you find at the home improvement store.

Richard and Rhonda Entrekin
99 Newell, 512
Maverick Hybrid Toad
Inverness, FL (when we're home Cool )
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#9

The first picture is the unloader valve. It opens up when the pumps turn off. I have had two fail and start leaking. The only source that I have found is Newell. (They get them from Valid).

I suspect that you could find an alternative that does same thing for far, far less money.

Ditto on what Richard said about push on fittings. (The dryer is notorious about cracking at the top and causing a leak).....The fittings going into dryer are also push on.

A good source for the DOT fittings is McMaster.com. (Not the cheapest, but they have wide selection and ship quickly and consistently).

Bill Johnson
Birmingham, Alabama
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#10

Carthan,
First, my apologies for interjecting non-applicable troubleshooting to your situation and confusing the situation.  Double ditto on what Richard said about those push fittings.  You may already know this but another source for DOT air fittings is NAPA.   If you sign up to AITA (America's Independent Truckers Association) NAPA will give you a discount.

Hope things go well with your fix!

Steve

Steve & Doris Denton
45' Newell #525, Bath & Half
2014 Honda CRV Toad
Summerfield, FL
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