Mains fuse F2 on PCB 40 blown High

Ideal Mains fuse F2 on PCB 40 blown Fault Code

Also written as MAINSFUSEF2ONPCB40BLOWN — same fault.

The Ideal Mains fuse F2 on PCB 40 blown fault code means: your boiler has lost power because an internal fuse has blown, likely caused by an electrical fault in the pump.. It appears on 1 Ideal model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 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 the Ideal Mains fuse F2 on PCB 40 blown 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.

Typical repair cost £180-350 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Ideal models that show the Mains fuse F2 on PCB 40 blown fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ideal Mains fuse F2 on PCB 40 blown fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026