How to reset a Vaillant Boiler

A Vaillant boiler that’s not turning on is not ideal, but many modern appliances are designed to ‘lockout’ when there’s a fault or risk for your safety. There could be unsafe conditions to keep operating such as a bad supply of gas, or a fault in the system.

Resetting the Vaillant Boiler

To reset the Vaillant boiler manually, press the reset button (3) and hold for one second.

Possible reasons for a lockout-

  1. Water pressure
  2. Ignition failure
  3. Heat exchanger blocked
Vaillant boiler
How to reset a Vaillant Boiler

If you are unable to resolve the ignition problem yourself by resetting the boiler three times, then consult a professional.