How much does it cost to fix Halstead error code 42?

Typical repair cost for the Halstead 42 fault is £60-250 including labour.

42 High

Halstead 42 Fault Code

Q: What does the Halstead 42 fault code mean?

Your boiler has detected that there is not enough water pressure or flow to operate safely, causing it to shut down shortly after lighting.

The Halstead 42 fault code means: your boiler has detected that there is not enough water pressure or flow to operate safely, causing it to shut down shortly after lighting.. It appears on 8 Halstead models in our database.

Technical description: Water flow failure/ Flame for a short period only. Low water pressure. No flow. Dry run protection

Typical repair cost £60-250 (including labour)

DIY fix possible

Check the pressure gauge on the front of the boiler or under the casing.If the needle is below 1 bar, use the external filling loop valves to top the system up to 1.5 bar.Ensure all radiator valves and isolation valves under the boiler are fully open.Reset the boiler once the correct pressure is reached.

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Halstead models that show the 42 fault code

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

Source

Halstead 42 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