How much does it cost to fix Halstead error code H.?

Typical repair cost for the Halstead H. fault is £80-150 including labour.

H. Medium

Halstead H. Fault Code

Q: What does the Halstead H. fault code mean?

Your boiler has accidentally entered a testing mode used by engineers, which means it is currently operating at a very low power setting and may not provide enough heat or hot water.

Also written as H — same fault.

The Halstead H. fault code means: your boiler has accidentally entered a testing mode used by engineers, which means it is currently operating at a very low power setting and may not provide enough heat or hot water.. It appears on 7 Halstead models in our database.

Technical description: SERVICE mode (flashing H.) - appliance runs at minimum CH output

Typical repair cost £80-150 (including labour)

Engineer required

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

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Halstead models that show the H. fault code

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

Source

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

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026