How much does it cost to fix Ariston error code A05?

Typical repair cost for the Ariston A05 fault is £150-250 including labour.

A05 High

Ariston A05 Fault Code

Q: What does the Ariston A05 fault code mean?

Your boiler is struggling to direct heat to your radiators or hot water taps because a valve inside the unit has failed to move into the correct position.

The Ariston A05 fault code means: your boiler is struggling to direct heat to your radiators or hot water taps because a valve inside the unit has failed to move into the correct position.. It appears on 7 Ariston models in our database.

Technical description: Motorised Valve

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 A05 fault code

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

Challenger 80E Repair: £150-250
Clas One Repair: £150-250
E-Combi One Repair: £150-250
E-Combi One 30 Repair: £150-250
Euro Combi 30 MFFI Repair: £160-280
Euro Prisma 24 Repair: £160-280
Microsystem 15 Repair: £150-250

Source

Ariston A05 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