BoilerFaultCodesTechnical description
Cylinder charging pump via accessory module
What causes this fault?
This fault occurs when the boiler's main control board loses its connection with the external pump responsible for heating your hot water tank. It is usually caused by a loose electrical connection, a failing communication module, or the pump itself developing an internal electronic fault that prevents it from responding to the boiler.
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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