RV Repair: hydro flame heater, hydro flame, propane regulator

Question
Just started having problems with this heater model # 8525-11.  heater fan comes on when thermostat is raised......then about 20 seconds later the burner tries to light with two or three short bursts.  But burner wont stay lit most of the time.

         thank you Arnold S.

Answer
check propane level.  check propane regulator.  check gas lines for spiders...they love to lay eggs in propane lines.  check ventilation for plugs.  system needs to breath or flame won't light.  check igniter or thermal couple for problems.  look outside at ventilation to see if it is plugged.  then after all else, suspect the gas valve.  

good luck