High
F15 on Glow-worm Ultracom 2 CXI

Your boiler's internal communication system is failing, which prevents it from talking to its sensors and stopping it from heating your home.

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

eBus Voltage failure

From this model's manual
Verified against the Glow Worm Ultracom 2 Cxi installation & service manual, page 48.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

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

F16View →F70View →

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