Safety: Turn off power before altering control wiring.

Check thermostat location: Ensure the Baxi room thermostat is not near heat sources, draughts, or direct sunlight.
Verify settings: Confirm the thermostat is set to the desired temperature and mode.
Test thermostat: Temporarily increase the setpoint to see if the furnace responds. If not, the thermostat or wiring may be faulty.
Professional adjustment: A technician can adjust boiler control curves or parameters on advanced Baxi controls.

Furnace runs but room temperature overshoots or undershoots the thermostat setting

Possible Causes