High
1F on Vaillant Turbomax Pro 28 2E

Your boiler has suffered a major electrical failure where the internal fuse blows instantly, meaning the main control board has likely short-circuited and stopped working.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Does fuse F1 blow immediately? Check/replace fan or replace electronic board

From this model's manual
Verified against the Vaillant Turbomax Pro 28 2e installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when a component inside the boiler fails and draws too much electricity, causing the internal fuse to blow instantly to protect the system. The most common reason is a short circuit within the main control board itself or a failed internal pump that has suffered an electrical surge.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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