BoilerFaultCodesYour boiler has stopped working because the electrical power coming from your home's mains supply is too low for it to run safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Power supply is less than 170V
What causes this fault?
This fault occurs when the electrical voltage entering the boiler drops to a level that is too low for the internal components to function. This is usually caused by a broader issue with the local power grid or an electrical fault within your home's wiring. In some cases, a failing internal circuit board can mimic this error by incorrectly reading the incoming power.
This fault can be more common during periods of extreme cold or high grid demand when the local electrical network is under significant strain.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like F17 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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