Propane shuts off after releasing start button. will not stay running. allpro propane 75000-125000 btu heater.

If you have replaced the thermocoupler and it still wont stay lit then replace the gas valve.

Sounds like the button is bad. Try replacing it

i have the exact same heater with the exact same problem. tested the thermocouple seems to be fine, tested the relay, it seems to be fine, could it be the gas valve????

Sounds like the thermocoupler or relay (if equipped) is bad.

Here is a test

Good luck!

is the sensor for the thermocouple located in the right spot in the flame,remove it and if you have access to a propane torch,heat the end till its red hot and leave it connected to the gas valve,then start the unit and this will tell you if the sensor is properly positioned in the pilot flame on the unit itself,if not you could have a defective new thermocouple or another safety device keeping it from staying lit or the gas valve is faulty

Bad button or switch.

If this is a new item then you will need to let the gas run alittle bit longer. If this is a used item then it sounds like you are going to need to replace the flame sensor. You may have to even do it on the new item. But usually for the first start you willl need to hold the pilot down for about 1 minute to really let things heat up in there then when you release all will work

the thermocouple is bad.it needs to send a signal to the gas valve to say it's okay to stay running.replace it and the problem should go away.if not let me know

Either a bad ignitor or gloplug.