I have a Mr. Heater Big Max 75k Btu natural gas heater and when I turn my thermostat on the main burner lights and stays lit for a 45 seconds to 2 minutes, then goes out. It repeats this process and will never stay lit, I have let do this up to five times and it never stays lit. On the led light it never flash anything other than the fast light
Heating & Cooling - Mr. Heater - Natural Gas Garage Heater - 45,000 BTU
Answers & Comments
Check the flame sensor is clean . Also check out the pressure switch . Check out the snap disk high and low temp .