BoilerFaultCodesYour boiler is not receiving enough electrical power from the mains supply to operate safely and has shut down as a precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Low power supply voltage
What causes this fault?
This fault occurs when the electrical voltage entering the boiler drops below the minimum level required for its electronic components to function correctly. The most common reason is an instability in your home's mains power supply or a loose connection within the boiler's internal wiring that is restricting the flow of electricity. In some cases, the boiler's main control board may be incorrectly detecting a drop in power due to a failing internal sensor.
This issue can be more frequent during periods of extreme weather or high local energy demand, which can cause temporary fluctuations or 'brownouts' in the national grid supply.
DIY fix possible
Check if other appliances in your home are struggling or if there is a local power cutEnsure the boiler's electrical fused spur switch is fully turned onReset the boiler by turning the selector switch to the 'R' position for 5 seconds
Find a Gas Safe engineer
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Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 0E33 — 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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