F9 or L9 or F8 or L8 High

Zanussi F9 or L9 or F8 or L8 Fault Code

Also written as F9ORL9ORF8ORL8 — same fault.

The Zanussi F9 or L9 or F8 or L8 fault code means: your boiler's main internal computer is failing to communicate correctly with its internal control systems, preventing it from safely starting up.. It appears on 1 Zanussi 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: PCB UNCONFIGURED/FAULTY OR GAS VALVE SHORT CIRCUIT
Typical repair cost £250-450 (including labour)

Engineer required

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

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Zanussi models that show the F9 or L9 or F8 or L8 fault code

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

Source

Zanussi F9 or L9 or F8 or L8 fault code information on this page is sourced and cross-checked against the official Zanussi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026