EE5566 High

Ariston EE5566 Fault Code

The Ariston EE5566 fault code means: your boiler has lost the signal from the sensor that monitors the temperature of the water being sent to your radiators, which prevents it from heating your home safely.. It appears on 3 Ariston models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Heating flow temperature probe in open 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 EE5566 fault code

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

Source

Ariston EE5566 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 7 July 2026