B08 Medium

Ariston B08 Fault Code

The Ariston B08 fault code means: your boiler is having trouble communicating with its internal timer, which means your scheduled heating programs may not turn on or off as expected.. It appears on 2 Ariston models 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: Time Clock
Typical repair cost £120-250 (including labour)

Engineer required

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

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Avoid the next call-out bill

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Ariston models that show the B08 fault code

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

Source

Ariston B08 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 31 August 2026