How much does it cost to fix Halstead error code E12?

Typical repair cost for the Halstead E12 fault is £120-200 including labour.

E12 High

Halstead E12 Fault Code

Q: What does the Halstead E12 fault code mean?

Your boiler has lost the ability to accurately measure the temperature of the water circulating back from your radiators, so it has safely shut down to prevent overheating.

The Halstead E12 fault code means: your boiler has lost the ability to accurately measure the temperature of the water circulating back from your radiators, so it has safely shut down to prevent overheating.. It appears on 6 Halstead models in our database.

Technical description: Heating return thermistor (NTC) fault

Typical repair cost £120-200 (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 E12 fault code

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

Eden Repair: £120-200
Eden 80 Repair: £120-200
Eden CBX/SBX Repair: £120-200
Netaheat 10/16E Repair: £120-200
Wickes 100 Repair: £120-200
Wickes 80 Repair: £120-200

Source

Halstead E12 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