I have a 1980 propane furnace. The pilot light will light. And the heat will kick on after the lighting. But after the furnace gets to the desired teperature the first time, the pilot light goes off and i have to start the process all over again. How do i keep the pilot lit and thereby keep the heat and the furnace on? Plese help. Thank you...

Exact brand and model number

Sounds like the blower is sucking out the piolit light, light piolit and turn on just fan only and see if it goes out if it does you probably have a cracked heat excanger. If it does not it may be a simple as change the t-coupler