CapnDean Posted January 20, 2021 Share Posted January 20, 2021 Learning as I go. While anchored at a rather notso level RV park - The small compressor that is there to bump up the system went off and wouldn't stop running after an extended period. Ultimately I killed the power to it in order to shut it up. I know that I have EITHER a bad 90-120pressure switch OR a compressor that is not building pressure. In my troubleshooting efforts, I got to thinking.... It would take forever for the small 12V compressor to air up the coach from scratch. I am trying to understand the process here so let me get this straight: The air bags are inflated by the main air system on the coach. That said, when I roll into a park, I have plenty of air to level up etc. As time marches on and the bags leak down (5 days) the small compressor ought to kick on, bring it up to 120# again and VIOLA another 5 days. Herein lies my question - If A man knew that his compressor was shot, he could start the main engine and allow the Coach air to bring it back into tolerance. Am I correct? If that is the case, then what stops the mini compressor from trying to air up the whole coach when it is parked? When I have left my coach un-used for any period of time, first thing that I do when I start it, is to wait for the main engine air compressor to bring the system up to pressure so that I will have brakes. Link to comment Share on other sites More sharing options...
Ivan K Posted January 20, 2021 Share Posted January 20, 2021 Your aux compressor should not kick in if you level the coach at arrival and then turn leveling off. That's what I do when boondocking, to preserve batteries. I have HWH system but would expect the same with yours. Link to comment Share on other sites More sharing options...
Frank Bergamo Posted January 20, 2021 Share Posted January 20, 2021 If you knew that your aux compressor was shot, then yes, you could start the engine to air up system to relevel coach. As Ivan said above, once level, turn off Valid remote, then aux compressor will not come on. I always make sure to turn off remote when leaving coach for a period of time so aux compressor will not activate while away. On my coach, I have also wired a switch from compressor to left arm control panel so I can turn off compressor any time, just in case I forget to turn off Valid remote. A little redundant, but as I age, I need all the help I can get. Hope this helps. Link to comment Share on other sites More sharing options...
Keith Moffett Posted January 20, 2021 Share Posted January 20, 2021 3 hours ago, CapnDean said: Learning as I go. While anchored at a rather notso level RV park - The small compressor that is there to bump up the system went off and wouldn't stop running after an extended period. Ultimately I killed the power to it in order to shut it up. I know that I have EITHER a bad 90-120pressure switch OR a compressor that is not building pressure. In my troubleshooting efforts, I got to thinking.... It would take forever for the small 12V compressor to air up the coach from scratch. I am trying to understand the process here so let me get this straight: The air bags are inflated by the main air system on the coach. That said, when I roll into a park, I have plenty of air to level up etc. As time marches on and the bags leak down (5 days) the small compressor ought to kick on, bring it up to 120# again and VIOLA another 5 days. Herein lies my question - If A man knew that his compressor was shot, he could start the main engine and allow the Coach air to bring it back into tolerance. Am I correct? If that is the case, then what stops the mini compressor from trying to air up the whole coach when it is parked? When I have left my coach un-used for any period of time, first thing that I do when I start it, is to wait for the main engine air compressor to bring the system up to pressure so that I will have brakes. What coach is always helpful info. On our Beaver the compressor pumps up a tank just for that compressor and shuts off. Link to comment Share on other sites More sharing options...
willbo777 Posted January 20, 2021 Share Posted January 20, 2021 The Valid system is different from the HWH in that the aux pump runs only based on the 90/120 pressure switch, turning off the leveling panel will not turn the aux pump off. I like others have wired in a switch to near my leveling panel so I can turn it off. The aux pump only pumps up a small leveling tank. I also moved my aux pump inside a cargo bay to get it out of the weather. If it runs and doesn't shut off the pump is bad or there is a leak between the pump and the tank. If your coach sits for 5 days normally without the aux pump running it appears you don't have much of a system leak. My pump runs 2-3 times a day for less than a minute. Monaco also hooked many of them up wrong, the check valve needs to be at the aux pump not at the tank. Link to comment Share on other sites More sharing options...
96 EVO Posted January 20, 2021 Share Posted January 20, 2021 7 hours ago, willbo777 said: Monaco also hooked many of them up wrong, the check valve needs to be at the aux pump not at the tank. I haven't moved my check valve, but when my compressor started running more frequently than normal, I removed the valve and sprayed a little lube into it. I can now go days without the compressor starting. Link to comment Share on other sites More sharing options...
CapnDean Posted January 20, 2021 Author Share Posted January 20, 2021 In addition to a bad pressure switch, I have discovered that there is a slight air leak at the intake air filter of small air pump. I confirmed this by removing the threaded in air filter and blocking the hole with my finger. I’m afraid that this means a bad diaphragm in the pump. Not completely sure Link to comment Share on other sites More sharing options...
Keith Moffett Posted January 20, 2021 Share Posted January 20, 2021 Taking good care of the Valid pump is a good idea. Ours went bad after 10 years but has been replaced 3 times since. I have considered going to Canada just to replace the system. Link to comment Share on other sites More sharing options...
willbo777 Posted January 20, 2021 Share Posted January 20, 2021 42 minutes ago, CapnDean said: In addition to a bad pressure switch, I have discovered that there is a slight air leak at the intake air filter of small air pump. I confirmed this by removing the threaded in air filter and blocking the hole with my finger. I’m afraid that this means a bad diaphragm in the pump. Not completely sure I replaced my pump several times, first off with Firestone 9285, and most recently with a Viair 350C. As I said I moved it into a bay compartment to get it out of the weather. I am very pleased with the Viair, when it runs, it takes half the time as the Firestone. It is almost an exact replacement and quite affordable. Link to comment Share on other sites More sharing options...
96 EVO Posted January 21, 2021 Share Posted January 21, 2021 (edited) With the air filter off, and the pump running ( tank drain open), give the intake a little mist of good lube oil. Don't drown it, just let it inhale a little mist. You may not have a bad pressure switch. Just all the air in your aux tank leaking back through your compressor. The 'check valve', isn't really a one way check valve. It has a cracking pressure, which will open up the valve to equalize the pressure on either side. Yeah, I spent some time studying this system! Some think this 'check valve' was installed in the wrong place, but if everything is working properly, it works fine where it is. Edited January 21, 2021 by 96 EVO 1 Link to comment Share on other sites More sharing options...
CapnDean Posted January 22, 2021 Author Share Posted January 22, 2021 Well, as it turns out... It was the pressure switch all along. A new switch and it works like a champ. It also shuts off when it is supposed to. 96 EVO thank you for the suggestion, I already did that in my efforts to cure the leak. it worked. I used just a squirt of Kroil - It did the trick. I am still not sure how the mini compressor plays with the main engine air compressor. I do know that the running the main will air it up so that the bags have enough air to level. I do know that as the bags bleed down and the coach levels by letting air out until it is level. Obviously it eventually would run out of air to let out, so IN comes the mini. So what stops the mini from coming on and charging the brakes and all. Link to comment Share on other sites More sharing options...
Paul J A Posted January 22, 2021 Share Posted January 22, 2021 Be sure the wires going to the Pressure switch have a loop or a low point before going to the switch so water does not run into the switch. Prevents premature failure of the switch. Link to comment Share on other sites More sharing options...
96 EVO Posted January 22, 2021 Share Posted January 22, 2021 (edited) 17 hours ago, CapnDean said: So what stops the mini from coming on and charging the brakes and all. The small leveling tank can also get air from the chassis secondary tank. There is a pressure protection valve at the output of the secondary tank that will only allow air to flow one way (towards the leveling tank), and only until the secondary tank get's below 65(?) psi. Air leaving the small tank just goes to the leveling valves/ manifolds. Has no way of reaching the brake system. Edited January 22, 2021 by 96 EVO Link to comment Share on other sites More sharing options...
Jdw12345 Posted October 22, 2021 Share Posted October 22, 2021 (edited) On 1/21/2021 at 10:57 PM, CapnDean said: Well, as it turns out... It was the pressure switch all along. A new switch and it works like a champ. It also shuts off when it is supposed to. 96 EVO thank you for the suggestion, I already did that in my efforts to cure the leak. it worked. I used just a squirt of Kroil - It did the trick. I am still not sure how the mini compressor plays with the main engine air compressor. I do know that the running the main will air it up so that the bags have enough air to level. I do know that as the bags bleed down and the coach levels by letting air out until it is level. Obviously it eventually would run out of air to let out, so IN comes the mini. So what stops the mini from coming on and charging the brakes and all. Could you please advise me as to where you got the new pressure switch from? Trying to diagnose my suspected non functioning auxiliary air system! Thank you! Edited October 22, 2021 by Jdw12345 Link to comment Share on other sites More sharing options...
Ivylog Posted October 22, 2021 Share Posted October 22, 2021 (edited) I have good luck finding things on EBay…. either 1/4” Pipe thread for $11 or 1/8” for $9.45. On at 90 and off at 120. Sorry but I haven’t figured out how to post a link to the item with my phone. Edited October 22, 2021 by Ivylog Link to comment Share on other sites More sharing options...
Paul J A Posted October 22, 2021 Share Posted October 22, 2021 Those pressure switches are available at most 4X4 off road Parts shops. Very popular for that application and alway less than most RV suppliers. 6 hours ago, Jdw12345 said: Could you please advise me as to where you got the new pressure switch from? Trying to diagnose my suspected non functioning auxiliary air system! Thank you! Those pressure switches are available at most 4X4 off road Parts shops. Very popular for that application and alway less than most RV suppliers. Link to comment Share on other sites More sharing options...
Jdw12345 Posted October 23, 2021 Share Posted October 23, 2021 (edited) Thank you! Edited October 23, 2021 by Jdw12345 Link to comment Share on other sites More sharing options...
W7BE_Bob Posted October 30, 2021 Share Posted October 30, 2021 Valid is very aware that Monaco incorrectly installed the check valve. They can send you the connectors (threads are different) to move the check valve to the output of the compressor instead of downstream after the pressure switch. The reason is obvious. Compressors can and do normally have small leaks which results in low pressure but not not past the correctly installed check valve which Monaco installed down stream of the pressure switch. Valid is in BC so there are extra shipping and customs considerations. I decided to order from Valid rather than trying to get the parts locally. My coach will now stay level for a month with Valid turned off, but if you have leaks then not so much. And leaks are why some choose to install a switch to disable the Valid pump. The valid pump/air tank is not connected to the main tanks or brakes. The valid air is connected to the air manifold with valves for each axle and the leveling system operates the valves for each wheel position as needed to level and maintain level. ie Inflating/deflating only the air bags. This is different then the system to maintain ride height. The service brakes are not designed to work when parked with the engine off. They may but only until the tank pressure is low. The ebrake has a seperate chamber with a very strong spring on each dual to activate the brake which occurs when the console ebrake air switch is OFF (meaning closed or pulled up) or the tank pressure drops below about 60 psi. The brake is disabled when there is suficient air pressure to pull back the spring and release the air brake. This is a standard design to active the air brakes when pressure is lost. Link to comment Share on other sites More sharing options...
96 EVO Posted October 30, 2021 Share Posted October 30, 2021 Interesting Bob! I haven't had too much issue with the check valve mounted where it is, but a few years ago misted a bit of lube oil into the compressor while running. One time since, I lubricated the check valve itself. I've never had any issues with the air springs bleeding down over time, and if I park with full air tanks, level, then turn off the leveling system, I can go over 10 days before the aux compressor will need to top up it's tank. I may give Valid a call and purchase their relocation kit. Link to comment Share on other sites More sharing options...
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