High
F9 or L9 or F8 or L8 on Ideal Logic Combi ESP1

Your boiler's computer system has lost its settings or is failing to communicate, meaning the boiler cannot safely operate. Because the central control unit is malfunctioning, you will currently have no heating or hot water.

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

PCB UNCONFIGURED OR FAULTY - SEE SECTION 3.19 IF FAULT PERSISTS REPLACE PCB

From this model's manual
Verified against the Ideal Logic Combi Esp1 installation & service manual, page 55.
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

F9View →L9View →F8View →L8View →

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