Wont stay lit

go to this site www dot desatech dot com. Here you'll find parts to repair your heater. a propane heater uses a millivolt generator to sense the flame. along it's cappilary are two push on spde connectors. these connect to the high limit temperature sensor which is mounted on the flame backplate of your heater. to see if it is the high limit shutting down your heater, jumper across the two spade connectors. if the heater stays on, this is your problem. if the flame still goes out, then the millivolt generator is shot.