Technical description
FLAME LOSS
What causes this fault?
This fault occurs when the boiler's internal sensors lose track of the flame after it has already started. The most common reasons are a buildup of carbon on the ignition parts or a blockage in the condensate trap that causes water to back up into the heat exchanger. It can also be triggered by an unstable gas supply or a faulty gas valve failing to maintain a steady flow.
This fault is more common during freezing winter temperatures, as a frozen external condensate pipe can cause water to back up and extinguish the flame.
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.