BoilerFaultCodesYour boiler has lost power because an internal fuse has blown, likely caused by an electrical fault in the pump.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Check pump for shorts between L/N and L/E. Disconnect pump and lead to PCB 41, renew fuse and reconnect to determine faulty item.
What causes this fault?
This fault occurs when an electrical component within the boiler draws too much current, causing a safety fuse on the control board to blow and cut all power. The most common reason is that the central heating pump has developed an internal short circuit or has seized, often due to a build-up of debris or water leaking into its electrical housing.
This issue is most frequent at the start of autumn when the heating is turned on for the first time after summer, as the pump is prone to seizing after long periods of inactivity.
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 Mains fuse F2 on PCB 40 blown — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Ideal Response 80 100 120 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.