How much does it cost to fix Remeha error code 3!?

Typical repair cost for the Remeha 3! fault is £120-210 including labour.

3! High

Remeha 3! Fault Code

Q: What does the Remeha 3! fault code mean?

Your boiler has stopped working because it thinks the main internal thermometer has developed an electrical fault and can no longer accurately measure water temperature.

Also written as 3 — same fault.

The Remeha 3! fault code means: your boiler has stopped working because it thinks the main internal thermometer has developed an electrical fault and can no longer accurately measure water temperature.. It appears on 17 Remeha models in our database.

Technical description: Temperature sensor failure - Flow temperature sensor short circuit

What causes the Remeha 3! fault?

This fault occurs when the boiler's control chip detects that the electrical signal from the main flow sensor has become unstable or interrupted. The most common reason is that the sensor's internal wiring has failed due to age and heat stress, or moisture has seeped into the electrical connection, causing a short circuit. Because the boiler no longer knows how hot the water is, it shuts down as a safety precaution to prevent overheating.

Typical repair cost £120-210 (including labour)

Engineer required

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

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Remeha models that show the 3! fault code

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

Source

Remeha 3! fault code information on this page is sourced and cross-checked against the official Remeha service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026