I had an issue 2 months after I got my 5th wheel with the frig not working on propane. I took it back in and they found a piece of styrofoam in the propane line that stopped the frig from working. If you are not double regulated and you know the valve right before the QD is on, this might be another possible check.
Jim and Carol
2012 Crusader 290RLT
2010 Ford F-250 King Cab Diesel
Harley Davidson Edition