How much does it cost to fix Ariston error code 2 04?

Typical repair cost for the Ariston 2 04 fault is £120-220 including labour.

2 04 Low

Ariston 2 04 Fault Code

Q: What does the Ariston 2 04 fault code mean?

Your boiler is having trouble communicating with the solar energy system because a heat sensor is disconnected or faulty, which may stop the solar panel integration from working correctly.

Also written as 204 — same fault.

The Ariston 2 04 fault code means: your boiler is having trouble communicating with the solar energy system because a heat sensor is disconnected or faulty, which may stop the solar panel integration from working correctly.. It appears on 9 Ariston models in our database.

Technical description: Solar collector temperature probe open / short circuit

Typical repair cost £120-220 (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 2 04 fault code

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

Source

Ariston 2 04 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