This room-temperature sensor is required by all Harman pellet stoves and inserts to use the “Room Temp” or “Automatic” mode setting on older units without a touchscreen.
A 4 BLINK error code at startup is triggered when the controller doesn’t detect this probe. This error usually means the probe is damaged but the error can also happen if the probe has become unplugged.
If your probe is missing or damaged the unit can still be used by selecting the”Stove Temp” or “Constant Burn” setting but you will lose the automatic temperature control.
When this probe is attached and functioning and, if the probe is placed properly, your Harman stove or insert should be able to regulate the desired temperature in the room within 1°F of the setpoint on the dial.