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.
Technical description: Thermistor cylinder open
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →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