BoilerFaultCodesTechnical description
Water shortage, temperature rise too quick. Pump blocked, insufficient pump output, air in appliance, water pressure too low
What causes this fault?
This fault occurs when the heat inside the boiler builds up too quickly because the heated water isn't moving through your radiators fast enough. The most common reasons are a failing circulation pump, a blockage in the system like sludge or limescale, or air trapped within the pipes.
This issue is more frequent during the first cold spell of autumn when the heating is turned back on after months of inactivity, as pumps can seize and debris can settle.
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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