How much does it cost to fix Chaffoteaux error code 5.iii?

Typical repair cost for the Chaffoteaux 5.iii fault is £90-160 including labour.

5.iii Medium

Chaffoteaux 5.iii Fault Code

Q: What does the Chaffoteaux 5.iii fault code mean?

Your boiler is struggling to provide hot water because the debris filter that cleans the water entering the system has become clogged, restricting the flow.

Also written as 5III — same fault.

The Chaffoteaux 5.iii fault code means: your boiler is struggling to provide hot water because the debris filter that cleans the water entering the system has become clogged, restricting the flow.. It appears on 3 Chaffoteaux models in our database.

Technical description: Hot water does not operate over temperature range - Inlet water filter blocked

Typical repair cost £90-160 (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 5.iii fault code

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

Source

Chaffoteaux 5.iii 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