How much does it cost to fix Ideal error code 88 H......4.......?

Typical repair cost for the Ideal 88 H......4....... fault is £150-250 including labour.

88 H......4....... High

Ideal 88 H......4....... Fault Code

Q: What does the Ideal 88 H......4....... fault code mean?

Your boiler has detected that the temperature monitoring system for the exhaust gases is not reading correctly, which means the boiler will stop working to ensure safety.

Also written as 88H4 — same fault.

The Ideal 88 H......4....... fault code means: your boiler has detected that the temperature monitoring system for the exhaust gases is not reading correctly, which means the boiler will stop working to ensure safety.. It appears on 1 Ideal model in our database.

Technical description: FLUE SENSOR

Typical repair cost £150-250 (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 88 H......4....... fault code

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

Isar M30 / M100 Repair: £150-250

Source

Ideal 88 H......4....... 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