BoilerFaultCodesYour boiler has detected an electrical issue with its power supply or wiring, meaning it cannot safely start the burner.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Phase error
What causes this fault?
This fault occurs when the boiler detects an inconsistency with the electrical supply, specifically that the live and neutral wires may be swapped or there is a lack of a solid earth connection. The most common reason is a recent electrical repair in the home or a faulty internal component that has disrupted the correct flow of electricity. Because the boiler requires a specific electrical polarity to safely detect a flame, it prevents the burner from firing until the wiring is corrected.
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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Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like E33 — 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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