I've noticed on our propane refrig that when running normally on propane, it's burner flame makes an audible roaring sound that can easily be heard outside when standing close to the outside ventilation grill, and can even be heard inside if I put my ear up to the cabinet wall where the refrigerator is mounted.
Last week my refrig quit cooling on propane, too (but cooling on 120 volt AC) - however there was still a flame in the burner when it was running on propane -> just too small of a flame, such that I could hardly hear it outside when standing close to the outside ventilation grill.
With the tip of a flat bladed screw driver I merely scraped the grey/black crud off around the slits in the tube where the propane comes out to burn and ... wa-la ... the flame became larger and it roared again. Our refrig now works fine on both 120 volt AC and propane!
