Hi,
May have a bad thermostat.Kinda rare,but does happen.Might turn thermostat on and off and see if there is a poof when burner kicks off.Is this a older heater or a newer model that has a enclosed burner?If this a whirlpool water heater,will explain a lot,hope I helped
May have a bad thermostat.Kinda rare,but does happen.Might turn thermostat on and off and see if there is a poof when burner kicks off.Is this a older heater or a newer model that has a enclosed burner?If this a whirlpool water heater,will explain a lot,hope I helped