Ok, I am having a problem with my NG wall mounted heater. It is a Empire SR30T, which has been here since we moved in. The problem is it works when it wants if it wants. The heat will stay on for 10 seconds at the least 5 minutes at the most. So I light the pilot and leave it on for about 5 minutes(Left it on for about 4 hours before) to let the thermocouple heat up. Pilot is tipping the thermocouple by 1/8”. Call for heat, 10 seconds later the fire and pilot gives in, what’s with that? Relight 5 minutes later, it might stay on for 20 seconds(Hopefully) shuts completely off again. Any ideas? I have cleaned the thermocouple(per sut buildup) and cleaned the pilot head. Thanks in advance.