I have a All-Pro propane heater model # Universal 85-FAC. I can get it to start but when I take my hand off the starter button it shuts off?

These models require electrical power to run the blower fan.
When you connect the electrical cord, the fan should turn on, then you should be able to start / ignite the propane. if the fan does not turn on when you connect the power cord, you will not be able to ignite the propane.

its the thermo coupler

Yes, I do. Master Distributors stocks parts for All Pro heaters. http://www.masterparts.net/

Google the make and model to find nearest supplier or the shop you bought it from

if it is propane fired, I would replace the thermocouple first.

I have the same problem with my Reddy heater 55-f. Is it thermal coupling or relay?

I plug a Thermostat in The power line to break the power when at temp. Once I start the heater using the reset button,when temp is reached and the themo calls for heat just the blower comes on only. I have a All Pro propane 50,000 to 85,000 btu heater thanks Ron

change the millivolt generator or check the two spade connectors on the millivolt's tube. wires go to a klixon temperator overload.

You may try calling Master Parts, they might have the part your looking for at 800-446-1446. You can find them online at www.masterparts.net. I hope this helps...

going through the backplate to the nozzle location is the thermocouple. it is a copper like tube that sits back from the actual flame. if you are looking for a replacement go to www dot desatech dot com.