BoilerFaultCodesYour boiler has stopped working because the water pressure in the central heating system is too low or a sensor has failed.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: CH pressure loss/pressure sensor faulty. Check/replenish CH system pressure. Find leaks. Check/replace pressure transmitter and cable.
What causes this fault?
This fault occurs when the internal sensor detects that the water pressure has dropped below the minimum level required to operate safely. The most common reason is a slow leak somewhere in your radiators or pipework, but it can also happen if the expansion vessel has lost its air charge and can no longer stabilize the pressure.
This issue is more frequent in autumn when homeowners first turn their heating back on after summer, as the change in temperature can reveal small leaks or failed seals.
DIY fix possible
Check the pressure gauge on the front of the boilerIf the pressure is below 1.0 bar, locate the filling loop (braided silver hose) under or near the boilerSlowly open the valves to top up the water until the gauge reads between 1.0 and 1.5 bar, then close them tightly
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A boiler cover plan would cover faults like A15 — no call-out fees, no surprises.
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