Not on my coach but on my crane. The information might help someone find an undetectable leak. After chasing and fixing leaks for about a week I was about to give up. I could hold air down to 30 lbs. over night but could not find any more leaks. Finally today I put a regulator on my shop air and set it to 130 lbs. which is the way I found all the other leaks. This time I took the air filter off the air compressor after disconnecting the output air line to eliminate the check valve. I still had air coming out of the intake port of the compressor. The line to the d-2 governor cutoff port has constant pressure and my unloader valves are letting air pass through. My compressor is a Haldex el1300 but the air compressor systems all work the same. I ordered the unloader rebuild kit and gaskets from Findit parts. I hope this fixes the last of the air leaks
Isnt the check valve supposed to isolate the compressor off load? Most compressors will pass air back through if not running.
The check valve isolates the air from the wet tank to the compressor. The governor shutoff line is always pressurized and goes to the unloader valve where it is supposed to stop the air from entering the compressor cylinders.