RV Repair: suburban heater problem, paper wasps, mud daubers

Question
I have a fairly new Suburban NT 12S propane heater. It will only light occasionally. I have good spark, measure 12.5volts d.c. from the converter, a new gas regulator and everything else in the camper works fine on gas. It seems like it doesn't always get enough gas. Could it be the gas valve or solenoids?

Answer
John, It very well could be the valve or even the solenoids on the valve. Also just because everything else works in the camper doesn't mean that the furnace will if you have no idea what the pressure is in the system. I seem to believe that model of furnace has a little hole in the face so you can watch the spark. The electrode should be adjusted to 3/8 inch from the burner for correct spark as well as enough propane and air. You may want to check outside in the exhaust vents and look for signs of paper wasps or mud daubers. These can also cut the air flow and cause it to not light. With a manometer you could use the port on the valve to see that there is sufficient pressure there. If the valve opens it usually opens all the way. These are just things you might want to look at to solve this problem. I hope this helps, Bill