Air Dryer Relief Valve popping - 06 Discovery
I just acquired a (new to me) 2006 Discovery 39S. I immediately noticed that the air dryer had problems as it was purging every 1-2 seconds at high RPM, and about every 10-30 secs at idle. The air gauges were holding around 105. My first thought was a bad check valve, but after closer inspection, the purge valve isn't popping at all. The sound I'm hearing is the high pressure relief valve.
I thought this valve was supposed to go off at 175psi. Both dash gauges show only 105. If this valve is somehow popping off at ~105psi, then that would explain a few things.
Is it reasonable to suspect that this valve is faulty?
Assuming that it is somehow bleeding off pressure below the governor setting, then my purge valve is never popping, so is my system full of water? Where's the wet tank on this unit?
'06 Fleetwood Discovery 39S