30 60 70 High

Chaffoteaux 30 60 70 Fault Code

Also written as 306070 — same fault.

The Chaffoteaux 30 60 70 fault code means: your boiler has lost its connection to the sensor that monitors your hot water cylinder temperature, causing it to stop heating your water.. It appears on 2 Chaffoteaux models 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: Thermistor cylinder open
Typical repair cost £120-220 (including labour)

Engineer required

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

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Chaffoteaux models that show the 30 60 70 fault code

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

Source

Chaffoteaux 30 60 70 fault code information on this page is sourced and cross-checked against the official Chaffoteaux service / installation manuals for each affected model.

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