70 High

British Gas 70 Fault Code

The British Gas 70 fault code means: your boiler has detected a technical internal error, likely caused by a software glitch or a failure in the main control board, preventing it from starting up safely.. It appears on 1 British Gas model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Heat output: 19.2 kW | Heat input: 19.4 kW | Gas vol. flow rate: 33.9 (l/min at tV/tR = 80/60°C)
Typical repair cost £280-450 (including labour)

Engineer required

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

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British Gas models that show the 70 fault code

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

Source

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

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026