On Thu, 13 Mar 2008 22:25:37 -0500, aribert
wrote:

Either a check valve is non-functional or one is needed. I
am leary of tearing open either the pressure relief valve or the top of
the compressor at the moment to see if there is a check valve since I
need to use the compressor right now and I am not certain I would be
able to diagnose a problem if I had either of the two valves apart.
Suggestions on what to look for when I finally tear into this thing?

It's typical on stationary compressors for the check valve to be
screwed directly into the tank. At first glance it may look like an
adapter fitting between the tank boss and the pump outlet line.
Grainger carries inexpensive generic replacements.

--
Ned Simmons