How much does it cost to fix Chaffoteaux error code 7.iii?

Typical repair cost for the Chaffoteaux 7.iii fault is £150-250 including labour.

7.iii High

Chaffoteaux 7.iii Fault Code

Q: What does the Chaffoteaux 7.iii fault code mean?

Your boiler has lost the air pressure needed to run smoothly, causing it to release excess water to prevent unsafe pressure levels within the system.

Also written as 7III — same fault.

The Chaffoteaux 7.iii fault code means: your boiler has lost the air pressure needed to run smoothly, causing it to release excess water to prevent unsafe pressure levels within the system.. It appears on 3 Chaffoteaux models in our database.

Technical description: Safety valve discharges - Vessel lost air charge

Typical repair cost £150-250 (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 7.iii fault code

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

Source

Chaffoteaux 7.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