20 High

Chaffoteaux 20 Fault Code

The Chaffoteaux 20 fault code means: your boiler has detected an internal electrical communication error, meaning the main control board cannot talk to the sensors or parts correctly.. It appears on 5 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: Wiring problem
Typical repair cost £120-£350 (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 20 fault code

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

Source

Chaffoteaux 20 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 7 July 2026