How much does it cost to fix Ariston error code B07?

Typical repair cost for the Ariston B07 fault is £150-250 including labour.

B07 High

Ariston B07 Fault Code

Q: What does the Ariston B07 fault code mean?

Your boiler is struggling to switch between heating your radiators and providing hot water, which means you will likely have no hot water or central heating until it is fixed.

The Ariston B07 fault code means: your boiler is struggling to switch between heating your radiators and providing hot water, which means you will likely have no hot water or central heating until it is fixed.. It appears on 6 Ariston models in our database.

Technical description: Microswitch for Diverter 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 B07 fault code

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

Challenger 80E Repair: £150-250
E-Combi One Repair: £150-250
E-Combi One 30 Repair: £150-250
Euro Combi 30 MFFI Repair: £120-220
Euro Prisma 24 Repair: £120-£210
Microsystem 15 Repair: £150-250

Source

Ariston B07 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