20 Most Recent Procom QL300TYLA Heater - Page 4 Questions & Answers

Because you are dealing with a gas appliance I suggest be very careful. I recommend call the gas company and have them come out and check it.

Sounds like thermostat may have a battery going bad as to not supply sufficient power to turn on the relays. As safety procaution when a signal is weak or no longer detected the heater shuts down.

Try a Honeywell universal thermocouple .

Sounds like when the cover is on it over heats. You need more air ventilation. Check for dirty filters or screen. Check whole machine. Not sure if that's the answer. Good luck.

Bad valve. Replace.

the noise could be a build up of unburnt gas ( slow leak in the line before the jet) that reaches a point where it ignites and blows out the jet flame This is a situation that you need to get a gas fitter in to find the fault or the next big boom could be the house exploding