AL41 High
Your boiler has detected that the water pressure in the system is too low to operate safely and has shut down to protect itself.
Technical description: Check system pressure – refill if necessary. If fault reoccurs, contact a heating engineer.
Typical repair cost: £0-120 (including labour)
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath or near the boiler.Slowly open the one or two taps/valves on the filling loop until you hear water moving.Watch the pressure gauge and close the taps firmly once the needle reaches between 1.0 and 1.5 bar.Press the 'Reset' button on the boiler control panel to clear the error.
Protect yourself from future repair bills
A boiler cover plan would cover faults like AL41 — no call-out fees, no surprises.
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Parts commonly replaced
- Filling loop
- Expansion vessel
- Pressure sensor
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