How much does it cost to fix Ariston error code A09?

Typical repair cost for the Ariston A09 fault is £150-250 including labour.

A09 High

Ariston A09 Fault Code

Q: What does the Ariston A09 fault code mean?

Your boiler has detected that water is not circulating correctly through the system, so it has safely shut down to prevent internal damage.

The Ariston A09 fault code means: your boiler has detected that water is not circulating correctly through the system, so it has safely shut down to prevent internal damage.. It appears on 9 Ariston models in our database.

Technical description: Pump Pressure Switch

Typical repair cost £150-250 (including labour)

Engineer required

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

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Ariston models that show the A09 fault code

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

Challenger 80E Repair: £120-250
Clas One Repair: £120-180
E-Combi One Repair: £120-250
E-Combi One 30 Repair: £120-250
Euro Combi 30 MFFI Repair: £120-280
Euro Prisma 24 Repair: £100-£250
Genus 24 MFFI Repair: £150-250
Micro Combi 27 MFFI Repair: £150-250
Microsystem 15 Repair: £120-250

Source

Ariston A09 fault code information on this page is sourced and cross-checked against the official Ariston service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026