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

Typical repair cost for the Heatline Flashing 70 fault is £120-180 including labour.

Flashing 70 Medium

Heatline Flashing 70 Fault Code

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

Your boiler is struggling to detect the temperature of your hot water, which may cause your taps to run cold or prevent the hot water from switching on reliably.

Also written as FLASHING70 — same fault.

The Heatline Flashing 70 fault code means: your boiler is struggling to detect the temperature of your hot water, which may cause your taps to run cold or prevent the hot water from switching on reliably.. It appears on 2 Heatline models in our database.

Technical description: Fault on DHW sensor

Typical repair cost £120-180 (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 Flashing 70 fault code

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

Source

Heatline Flashing 70 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