BoilerFaultCodesYour boiler has shut down because it believes the internal water pressure is too low or it is getting too hot inside.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Water pressure switch or flue thermostat failure
What causes this fault?
This fault occurs when the boiler's safety sensors detect that there isn't enough water pressure to operate safely or that the internal exhaust gases are reaching dangerous temperatures. It is often caused by a leak in the system, a failing pressure sensor, or an internal component like the expansion vessel losing its air charge. When these conditions are met, the boiler shuts down immediately to prevent serious damage to the heat exchanger.
This issue is frequently seen in autumn when homeowners turn their heating back on for the first time, as small leaks or loss of pressure over the summer months become apparent.
DIY fix possible
Check the pressure gauge on the front of the boilerIf the pressure is below 1 bar, use the filling loop to top it up to 1.5 barReset the boiler to see if the error clears
Find a Gas Safe engineer
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A boiler cover plan would cover faults like 912 — no call-out fees, no surprises.
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Ideal Systemiser SE is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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