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Author Topic: air gauge  (Read 231 times)

Forrest King

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air gauge
« on: November 07, 2019, 12:06:04 PM »
what do the red an green needles on air gage mean. my green gage bleeds down over night. where should i start looking for a leak?
Forrest King
2006 Monterey Montclair 40 ft
cat c-9

Mike Shumack

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  • Orlando, Florida
Re: air gauge
« Reply #1 on: November 07, 2019, 01:00:30 PM »
The air system has a "Primary" and "Secondary" side/system. That is done so if air is lost to one "side" (like a hose blows) you will still be able to brake with the air in the other side. The different needles (or gauges, if you have two) will display the air pressure for each side. Usually the Green is the "Primary" side which is rear brakes.

Here's a basic diagram of how it looks (the different color line represent the different sides).

- Mike

'05 Beaver Patriot Thunder 525, Vicksburg, CAT C13, Allison 4000MH, HydraLift
Orlando, FL

Fred Brooks

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  • RVIA Certified Luxury Technician 49 years, Retired
Re: air gauge
« Reply #2 on: November 07, 2019, 01:08:41 PM »
   Forrest, the red and green needles on your air gauge represent the air pressure in your primary and secondary air tanks. The red needle is your rear air brakes only. It will move only when the brakes are applied. The green needle is your secondary air tank which is your front brakes, air ride suspension, horn and other accessories, When driving, you will see the green needle go from 120psi down to 90psi and then back up to 120psi. As you drive the coach is constantly leveling itself so it uses air to do that. When the air pressure gets down to 90psi the air compressor on the engine comes on and builds pressure back up to 120psi and you hear the reciever/dryer cycle and purge contaminants from the compressor and dryer.
   Safety system works this way, If the coach has an issue with the air compressor or you start losing air pressure for what ever the issue, you get a warning buzzer and light to alert you at about 70 to 80psi. If this happens, find a place to pull off the road safely. If you don't, when the air pressure gets down to 40psi it starts to apply the park brake. Now you will come to a stop on the road. Turn on your flashers, exit the coach and get away from it. Fred
Fred & Cindy Brooks
2000 Marquis, Jasper
C-12 Wild Cat (U of A)
2014 Honda CRV
Proverbs 3: 5 & 6

Jason Worman

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Re: air gauge
« Reply #3 on: November 08, 2019, 04:07:10 PM »
Fred,

Just a follow up question. So my air gauges while parked will slowly decrease, within about two weeks the needles drop to zero. Should I run the engine to air up the system?

Thank you
Jason Worman
2018-
91 Contessa 36 Foot
3116 CAT

Fred Brooks

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Re: air gauge
« Reply #4 on: November 08, 2019, 06:25:22 PM »
  Jason, nope. 2 weeks is above normal time. May want to level her if you have hydraulic jacks if you like. Fred
Fred & Cindy Brooks
2000 Marquis, Jasper
C-12 Wild Cat (U of A)
2014 Honda CRV
Proverbs 3: 5 & 6