How much does it cost to fix Chaffoteaux error code 30-80 (M, L, M, L, M, M)?

Typical repair cost for the Chaffoteaux 30-80 (M, L, M, L, M, M) fault is £120-200 including labour.

30-80 (M, L, M, L, M, M) Medium

Chaffoteaux 30-80 (M, L, M, L, M, M) Fault Code

Q: What does the Chaffoteaux 30-80 (M, L, M, L, M, M) fault code mean?

Your boiler has detected an internal sensor failure affecting the hot water supply, meaning it cannot accurately tell if the water is hot enough to use.

Also written as 3080MLMLMM — same fault.

The Chaffoteaux 30-80 (M, L, M, L, M, M) fault code means: your boiler has detected an internal sensor failure affecting the hot water supply, meaning it cannot accurately tell if the water is hot enough to use.. It appears on 2 Chaffoteaux models in our database.

Technical description: Thermistor sanitary bypassed.

Typical repair cost £120-200 (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 30-80 (M, L, M, L, M, M) fault code

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

Source

Chaffoteaux 30-80 (M, L, M, L, M, M) 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