8.iv Medium

Chaffoteaux 8.iv Fault Code

Also written as 8IV — same fault.

The Chaffoteaux 8.iv fault code means: your boiler is struggling to circulate water because the internal debris filter has become clogged, causing the pump to strain and make unusual noises.. It appears on 3 Chaffoteaux models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Pump noisy - Water filter blocked
Typical repair cost £120-220 (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 8.iv fault code

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

Source

Chaffoteaux 8.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