BoilerFaultCodesTechnical description
External pump
What causes this fault?
This fault occurs when the boiler detects that an additional external pump, which helps move water through your heating system, has failed or lost electrical power. The most common reason is an electrical fault in the pump itself or a break in the wiring connecting the pump to the boiler's main control board. Without this pump operating, the boiler cannot safely distribute heat, leading it to shut down to prevent overheating.
This fault is frequently seen at the start of autumn when heating systems are turned back on after months of inactivity, which can cause external 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.