WE CAN NOT GET OUR HEATER TO START.TRYING TO REPLACE THE SPARK PLUG IN IT TO SEE IF THAT IS THE ISSUE BUT CAN NOT GET IT OUT TO CK IT.THE THERMOSTAT KICKS ON AND THE BLOWER KICKS ON AND IT IS GETTING PROPANE TO IT BUT WILL NOT KICK ON AND HEAT.ANY IDEAS?????

SORRY I LEFT OUT THE IMPORTANT INFO IT IS A

SOL-AIRE
MODEL #16-21
SERIAL # 10697
IT IS THE ORIGINAL HEATER IN IT SO IT IS A 1973.
THANKS AGAIN FOR ANY HELP

First place to look is the "Sail Switch"; the fan blows air on a sheetmetal "sail" which moves and closes a microswitch, which in turn opens the gas valve and/or the igniter. Search in tech forums. Good luck.

Thank u will have to check this.