Heater is at 82F & is turning on and off every min or so. when the power is turned off & on it looks like a code o88 then r3 it fires up runs for a few min then shuts off. lifting the control board off and looking under there is NO lights on for codes. this heater has had a new Tube sheet coil assembly & a Thermal Regulator Kit this year. Last year it got a Thermistor & Stack Flue Sensor.