Technical description
Flashing slow (Burner Lockout)
What causes this fault?
This fault occurs when the boiler attempts to start up but cannot successfully ignite the gas to create a flame, or if the flame is lost during operation. The most common reasons include a lack of gas supply to the unit, worn-out ignition components that can no longer create a spark, or a build-up of carbon on the sensor that detects the heat.
This issue can become more frequent during the first cold snap of winter when components that have been idle over summer are suddenly put under heavy strain.
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.