BoilerFaultCodesWhat the manual says
Manufacturer manualCirculation pump
From this model's manual
Verified against the Vaillant Ecotec Plus 826 installation & service manual.
What causes this fault?
This fault occurs when the boiler's internal pump fails to circulate water effectively through the heat exchanger. The most common reasons are a mechanical failure of the pump motor, a buildup of sludge blocking the internal components, or air trapped within the unit preventing the pump from turning.
This fault is frequent in autumn when heating systems are switched back on after a summer of inactivity, which can cause the pump 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.
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