BoilerFaultCodesTechnical description
Water level control
What causes this fault?
This fault occurs when the system's internal sensors detect that the water pressure has dropped too low for the boiler to operate safely. The most common reasons are a leak somewhere in the pipework or radiators, or an expansion vessel that has lost its air charge and can no longer stabilize the pressure. In some cases, the water pressure sensor itself may have failed or become blocked with system debris.
This issue is more frequent in autumn when the heating is turned back on after a long break, as underlying leaks or pressure drops often become apparent during the first full cycle.
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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