10.i Medium

Chaffoteaux 10.i Fault Code

Also written as 10I — same fault.

The Chaffoteaux 10.i fault code means: your boiler is struggling because it cannot pump enough water through the system, causing it to rapidly turn on and off to protect itself.. It appears on 1 Chaffoteaux model 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: Rapid cycling high/low or high/low/off - Low water flow rate
Typical repair cost £120-250 (including labour)

DIY fix possible

Check your central heating pressure gauge and top it up to 1.5 bar if lowEnsure all radiator valves are fully openCheck that your external pump speed setting has not been turned down

Find a Gas Safe engineer

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

Gas Safe Register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like 10.i: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Chaffoteaux models that show the 10.i fault code

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

Source

Chaffoteaux 10.i 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 7 July 2026