How much does it cost to fix Ariston error code EE 9999?

Typical repair cost for the Ariston EE 9999 fault is £250-450 including labour.

EE 9999 High

Ariston EE 9999 Fault Code

Q: What does the Ariston EE 9999 fault code mean?

Your boiler's main control computer is experiencing a general communication error, causing the system to stop working as a safety precaution.

Also written as EE9999 — same fault.

The Ariston EE 9999 fault code means: your boiler's main control computer is experiencing a general communication error, causing the system to stop working as a safety precaution.. It appears on 4 Ariston models in our database.

Technical description: Problem within the electronic system

Typical repair cost £250-450 (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 EE 9999 fault code

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

Source

Ariston EE 9999 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