BoilerFaultCodesTechnical description
No feedback from the modulating gas valve. The gas valve relay is defective – press the reset button and apply burner start, wait to see if fault reoccurs, if it does the gas valve needs replacing
What causes this fault?
This fault occurs when the boiler's main computer loses touch with the gas valve that controls the fuel flow. It is usually caused by a physical failure of the electronic relay on the control board or a malfunction within the gas valve's internal motor. Because the boiler can no longer verify if the gas is being turned on or off safely, it shuts down as a protective measure.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register →