Vaillant Temperature Limiter 0020143455

The Vaillant 0020143455 is a temperature limiter used on Vaillant ecoTEC VU and VU GB open-vent boiler models. It acts as a safety cut-out, interrupting the burner when the sensed temperature exceeds the set limit. It is a serviceable control component within the boiler's thermostat and safety circuit.

• The boiler locks out or fails to fire, with the limiter tripping repeatedly.
• The appliance will not reset after a lockout, or resets only briefly before cutting out again.
• Overheat faults recur once the boiler reaches operating temperature.
• The limiter shows visible damage, corrosion or a loose or degraded connection.
• Continuity testing across the limiter indicates it is permanently open or permanently closed.

• Confirm the boiler model and variant against the fitment list above.
• Check the existing limiter's part number and mounting arrangement before removal.
• Isolate the electrical supply and the gas supply before working on the boiler.
• Verify the fault is with the limiter itself and not with the sensor, wiring or control board.