F 12 High

Ideal F 12 Fault Code

Also written as F12 — same fault.

The Ideal F 12 fault code means: your boiler has detected that the water pump is stuck and cannot move the water around your heating system properly, which has caused the boiler to switch itself off.. It appears on 9 Ideal models 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: Pump Rotor Blocked: Clear blockage
Typical repair cost £120-250 (including labour)

Engineer required

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

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Ideal models that show the F 12 fault code

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

Source

Ideal F 12 fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026