High
F13 on Glow-worm Xtramax HE

Your boiler's main control board has encountered an internal electronic error, meaning the 'brain' of the system can no longer manage the heating and hot water safely.

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

Main PCB fault.

From this model's manual
Verified against the Glow Worm Xtramax He installation & service manual, page 33.
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 the boiler's internal computer experiences a critical electronic failure or a 'brain freeze' that prevents it from processing commands. It is typically caused by a short circuit on the control board, aged components failing over time, or a communication error between the board and the wiring harness.

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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Related fault codes

F1View →F11View →

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