How much does it cost to fix Chaffoteaux error code 6.iii?

Typical repair cost for the Chaffoteaux 6.iii fault is £80-150 including labour.

6.iii High

Chaffoteaux 6.iii Fault Code

Q: What does the Chaffoteaux 6.iii fault code mean?

Your boiler has stopped working because it cannot detect enough water pressure inside the system to operate safely.

Also written as 6III — same fault.

The Chaffoteaux 6.iii fault code means: your boiler has stopped working because it cannot detect enough water pressure inside the system to operate safely.. It appears on 3 Chaffoteaux models in our database.

Technical description: No main burner - No water

Typical repair cost £80-150 (including labour)

DIY fix possible

Locate your boiler's filling loop (the silver braided hose under the unit)Slowly open the valves on the loop to let water into the systemWatch the pressure gauge on the front until the needle reaches 1.5 bar, then securely close the valves

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Chaffoteaux models that show the 6.iii fault code

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

Source

Chaffoteaux 6.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