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

Typical repair cost for the Chaffoteaux 7.iv fault is £250-450 including labour.

7.iv High

Chaffoteaux 7.iv Fault Code

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

Your boiler has developed an internal leak between its two water systems, causing the pressure to rise and trigger a safety release valve.

Also written as 7IV — same fault.

The Chaffoteaux 7.iv fault code means: your boiler has developed an internal leak between its two water systems, causing the pressure to rise and trigger a safety release valve.. It appears on 3 Chaffoteaux models in our database.

Technical description: Safety valve discharges - Secondary heat exchanger (water to water) internal water leak

Typical repair cost £250-450 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Chaffoteaux models that show the 7.iv fault code

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

Source

Chaffoteaux 7.iv 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