BoilerFaultCodesTechnical description
Burner control switches to lockout
What causes this fault?
This fault occurs when the water inside the boiler reaches an unsafe temperature, triggering a safety sensor to cut the power to the burner. The most common reasons include a failing pump that isn't moving water away from the burner quickly enough, or a buildup of debris and sludge that is restricting flow through the heat exchanger.
This issue often surfaces during the first cold spell of autumn when the heating is turned back on after sitting idle all summer, which can cause internal pump components to seize.
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.
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