BoilerFaultCodesTechnical description
Water pressure switch open (low system pressure)
What causes this fault?
This fault occurs when the pressure of the water circulating through your pipes and radiators drops below a safe level, causing the safety switch to cut power to the boiler. The most common reasons are a slow leak somewhere in the heating system or a loss of air pressure in the expansion vessel, which helps manage water volume as it heats up.
This issue often appears in autumn when the heating is turned back on after summer, as the change in temperature can highlight small leaks or reveal that pressure has slowly seeped away during months of inactivity.
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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