How much does it cost to fix Ideal error code -. / Y?

Typical repair cost for the Ideal -. / Y fault is £150-300 including labour.

-. / Y High

Ideal -. / Y Fault Code

Q: What does the Ideal -. / Y fault code mean?

Your boiler is stuck on the heating setting and cannot control its temperature properly, leading to overheating or a lack of hot water.

Also written as Y — same fault.

The Ideal -. / Y fault code means: your boiler is stuck on the heating setting and cannot control its temperature properly, leading to overheating or a lack of hot water.. It appears on 1 Ideal model in our database.

Technical description: Unit is constantly fired for the central heating and does not modulate in reverse direction. The central heating installation is overheated or not sufficiency heated; the hot water tank is not heated. Unit is constantly operative for the central heating, at the capacity adjusted with the hot water potentiometer.

Typical repair cost £150-300 (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 -. / Y fault code

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

Maximiser SE Repair: £150-300

Source

Ideal -. / Y 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 27 April 2026