BoilerFaultCodesYour boiler has detected that the electrical wiring coming into the unit is connected the wrong way around, preventing it from starting up for safety reasons.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Reversed Polarity
What causes this fault?
This fault occurs when the live and neutral electrical wires are switched at some point in the circuit, which prevents the boiler's safety systems from operating correctly. It is most commonly triggered following recent electrical work in the home or if a plug-in appliance has caused a fault in the local power supply. In some cases, a failing main circuit board can incorrectly detect this issue even if the wiring is correct.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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 LED 1 (RESET) Slow Flashing (2Hz), LED 2 (BURNER LIT) Slow Flashing (2Hz) Simultaneous — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm Micron 30ff is discontinued — time for a new one?
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.
Affiliate links — we may earn a commission at no extra cost to you.