High
F10 – A10 on Ferroli iBoiler 28

Your boiler's internal sensor that detects water flow has stopped working properly, meaning the system doesn't know when to turn the heat on or off.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Flow sensor error

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer
Search the official register →

Related fault codes

F11View →F14View →

Related guides you might find useful

No hot water but heating works

Almost always a stuck diverter valve on combis.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →