How much does it cost to fix Remeha error code 6.4.2 Thermostats?

Typical repair cost for the Remeha 6.4.2 Thermostats fault is £120-250 including labour.

6.4.2 Thermostats High

Remeha 6.4.2 Thermostats Fault Code

Q: What does the Remeha 6.4.2 Thermostats fault code mean?

Your boiler has detected that a safety thermostat has tripped, causing it to shut down to prevent the system from overheating.

Also written as 642THERMOSTATS — same fault.

The Remeha 6.4.2 Thermostats fault code means: your boiler has detected that a safety thermostat has tripped, causing it to shut down to prevent the system from overheating.. It appears on 2 Remeha models in our database.

Technical description: Shutdown / lock out

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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Remeha models that show the 6.4.2 Thermostats fault code

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

Source

Remeha 6.4.2 Thermostats 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