BoilerFaultCodesTechnical description
Pump / water shortage (no pressure increase when pump is starting)
What causes this fault?
This fault occurs when the boiler's internal computer fails to detect a small required rise in water pressure when the pump starts up. The most common reasons are a pressure sensor that has become blocked with system sludge or a pump that has seized and is no longer moving water through the heat exchanger.
This fault is frequently seen in autumn when the heating is turned back on for the first time, as pumps can seize after being idle throughout the summer months.
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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