[dannymarilyn]

Dear Dennis, The outflow check valve was the first fitting connected to the nipple on the compressor cylinder head. The outflow went through the check valve into the compression fitting which goes into the belly of the coach on ours (#277). Our compressor sitting on a shelf just above the generator cooling blower in right front compartment. When I reinstalled the compressor, I trimmed the insulation off the wall separating the compartment from the generator box. The insulation was hindering cooling air flow around the inside cylinder head on the compressor. I'd suggest disconnecting the outflow hose and remove the fittings connected to the compressor. Don't try very hard to remove the brass fitting screwed into the head. The heads are aluminum and the brass corrodes into the head and won't come out. On ours, the fitting out of the head is a 90°, then the inline check valve, then connecting to the compression fitting. I re-plumbed everything with DOT
compression fittings - they don't leak! On ours, the other head mounts the pressure relief valve in that head. The compressed air travels under the heads to merge. As long as you are removing brass to brass fittings, no problems. When you remove the valve, just look through it.
You'll see the one-way valve. You can suck air through it one way and nothing in the other way! I bought one in a hurry from Fleet Pride. I have two spares from E-bay for about $25 apiece. It should be 1/4" NPT sized. I used 1/4" brass fitting from local hardware store for nipples and connectors for my road kit. Let me know if you wish pictures. deg