How much does it cost to fix Heatline error code 70 Flashing?

Typical repair cost for the Heatline 70 Flashing fault is £120-200 including labour.

70 Flashing High

Heatline 70 Flashing Fault Code

Q: What does the Heatline 70 Flashing fault code mean?

Your boiler is struggling to detect the temperature of the water coming out of your taps, which means it will likely stop providing hot water until this is resolved.

Also written as 70FLASHING — same fault.

The Heatline 70 Flashing fault code means: your boiler is struggling to detect the temperature of the water coming out of your taps, which means it will likely stop providing hot water until this is resolved.. It appears on 2 Heatline models in our database.

Technical description: Fault on DHW sensor

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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Heatline models that show the 70 Flashing fault code

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

Source

Heatline 70 Flashing fault code information on this page is sourced and cross-checked against the official Heatline service / installation manuals for each affected model.

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