Furnace display indicates flue gas sensor fault, burner inhibited

Safety: Switch off power and allow the flue to cool before touching the sensor.

• Locate sensor: Find the flue gas temperature sensor at the flue outlet of the Hoval furnace.
• Inspect wiring: Check the cable for cuts, crushed sections, or signs of overheating. Ensure the plug is fully seated on the control board.
• Check mounting: Confirm the sensor probe is properly inserted into the flue pocket and secured with its clamp or screw.
• Clean contacts: If accessible, unplug the sensor and clean the contacts with electrical contact cleaner. Reconnect firmly.
• Reset and test: Restore power and reset the alarm. If the fault persists, the sensor is likely defective and should be replaced with a Hoval-approved part.