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Topic: Protection valve? (Read 460 times) previous topic - next topic

Protection valve?

I see protection valve on my air system schematics. Is that the "check valve" that ensures air only flows one direction? Or is it something different that could possibly close at a certain PSI?

I am still trying to figure out what would prevent my front air tank from ever dropping below 75psi. I get period drops from 105ish to 75psi when I hit a bump but it ALWAYS drops to the same PSI of 75. I seems there is a momentary leak, the pressure drops to 75 and something "plugs" the leak, and then the tank eventually fills back up again.

If not the protection valve, is there anything else that would prevent the tank from leaking out when a certain PSI is reached? I'm not ruling out the fact that one of my check valves has failed and I actually have a leak somewhere else in the system that manifests itself in the front tank.

EDIT: BTW, line 55 in the attached image goes to the front ride-height valve

Re: Protection valve?

Reply #1 –
Yes the air protection valve keeps the non-brake air operated items from draining the tank below the set point so you still have brakes.  For exmample if an air spring ruptured or an air hose to a non brake item burst, you do not lose all of your air.

Re: Protection valve?

Reply #2 –
When my Norgren valves were exhausting air all the time the air would drop to 60 lbs. and then hold.

Re: Protection valve?

Reply #3 –
Quote from: oldguy –
When my Norgren valves were exhausting air all the time the air would drop to 60 lbs. and then hold.
I know for a fact that the Norgren valve that feeds the step cover has a leak in it... and I'm just now seeing the little line (#39) shooting south from the protection valve to the step/slide cover. I should be able to close that pressure regulator and eliminate that as a suspect, no?
 

Re: Protection valve?

Reply #4 –
To test for leaks I just capped the line going to the first Norgren Valve