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rick.rutel · 06-28-2017, 12:53 PM

I have a 2008 Monaco Camelot with an air bag leveling system. There is a small compressor located near the generator compartment that helps keep the coach level when parked and air pressure is low in the chassis system. The compressor would not shut off and was causing the small tank to sneeze every few minutes. The power and ground wires to the pump were quite hot. I disconnected the wires and pulled the valve after reading in another forum that the valve was likely faulty. I purchased two replacement valves at the local Frieghtliner dealer. One has writing indicating NC for never closed, the other had no writing on it at all. In checking the manual, there is no indication which switch I should use. Given the research, it seems the generic 90 - 120 psi switch should be the correct one. It is an exact exterior match for the original. Unfortunately, after replacing the switch, the same situation is occurring. Ideas?

cvbdsl · 06-28-2017, 02:43 PM

I just got a 2008 HR Scepter 42 PDQ last week that has the same system.
To turn off auto leveling it says to turn the power off at the leveling system switch beside the driver.

Could your problem lie further up the chain with the leveling switch keeping power to the compressor? Just guessing.

Could you pull up the switch panel and disconnect any power to it? May indicate where the problem lies.

Chris

mackwrench · 06-28-2017, 03:06 PM

NC = normally closed (not never closed)

This means air will not come through valve unless switch is on or something tells it to open allowing air to system.

BarryG20 · 06-28-2017, 03:18 PM

While I am totally unfamiliar with that system if the switch is good wouldn't that indicate a leak in the sytem that it is trying to keep up with?

rick.rutel · 06-28-2017, 03:44 PM

Quote:

Originally Posted by mackwrench

NC = normally closed (not never closed)

This means air will not come through valve unless switch is on or something tells it to open allowing air to system.

Thanks. I couldn't remember the correct term. Interestingly enough, I have yet to find out which valve should be on the coach. The unit I took off had rust in the stem, so I'll assume that may have caused it to remain in the open position. I've backtracked the system spraying any connectors and the bags with soapy water. No bubbles. According to Monaco, once the coach is level, the leveling system will go into a "sleep mode" and "awaken" every twenty minutes or so to check the system. It is not supposed to turn on at all if the main power switch to the leveling system is off, yet it does. Maybe a relay?

windsorbill · 06-28-2017, 05:30 PM

Do you know what brand leveling you have? I have a valid system and Monaco put the pressure sensor switch in the wrong place. When my switch failed, I got a new one from Valid and installed it in the correct place. Never an issue after that.

Dtwallace · 06-28-2017, 07:14 PM

From your description, the sneeze you hear is the overpressure pop off valve opening due to the compressor not stopping at the pre set value. This is your safety device.

Your compressor is receiving power when it shouldn't, through one of two paths.

Two items to look would be the pressure switch that is factory set at the 125PSI that is the normal pressure for shut off (opening the control circuit), or the relay that could be stuck closed (not opening the compressor power circuit) once the switch has opened.

Your wires are hot and should be from the extended run of the compressor.

Since your unit is a few years old, change the pressure switch out and the relay after it and you should have a trouble free system.

The pressure switch should be (NC) normally closed when there is no pressure applied.
this way it will complete the control circuit to the relay to energize the power circuit to the compressor.

This condition should not have effected any other part of your air system, and is a rare but possible occurrence.

DTW

rick.rutel · 06-28-2017, 07:25 PM

Quote:

Originally Posted by Dtwallace

From your description, the sneeze you hear is the overpressure pop off valve opening due to the compressor not stopping at the pre set value. This is your safety device.

Your compressor is receiving power when it shouldn't, through one of two paths.

Two items to look would be the pressure switch that is factory set at the 125PSI that is the normal pressure for shut off (opening the control circuit), or the relay that could be stuck closed (not opening the compressor power circuit) once the switch has opened.

Your wires are hot and should be from the extended run of the compressor.

Since your unit is a few years old, change the pressure switch out and the relay after it and you should have a trouble free system.

The pressure switch should be (NC) normally closed when there is no pressure applied.
this way it will complete the control circuit to the relay to energize the power circuit to the compressor.

This condition should not have effected any other part of your air system, and is a rare but possible occurrence.

DTW

Thank you very much for the reply. I purchased the NC and regular pressure switches at the truck dealer and of course, put in the non NC unit. Luckily, it's a ten minute job to replace it. I will replace the relay as well. Thanks again for the information!