BoilerFaultCodesYour boiler has detected that there is not enough water in the heating system to operate safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Indicates insufficient system pressure or a faulty low water pressure switch.
What causes this fault?
This fault occurs when the water pressure inside your heating system drops below a safe level, preventing the boiler from firing up to protect the internal components. The most common reasons for this are a leak somewhere in the pipework or radiators, or simply needing to top up the system after bleeding air from your radiators.
This issue is frequently seen in autumn when homeowners turn their heating back on for the first time or bleed their radiators to prepare for winter.
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath or near the boilerSlowly open the tap or taps on the filling loop to allow water into the systemMonitor the pressure gauge until it reaches between 1 and 1.5 bar, then close the taps fully
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like Low water pressure LED flash — no call-out fees, no surprises.
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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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