How much does it cost to fix Keston error code E 37?

Typical repair cost for the Keston E 37 fault is £120-220 including labour.

E 37 High

Keston E 37 Fault Code

Q: What does the Keston E 37 fault code mean?

Your boiler has lost the signal from one of its internal temperature sensors, meaning it cannot correctly measure the temperature of the water returning to the system and has stopped working as a safety precaution.

Also written as E37 — same fault.

The Keston E 37 fault code means: your boiler has lost the signal from one of its internal temperature sensors, meaning it cannot correctly measure the temperature of the water returning to the system and has stopped working as a safety precaution.. It appears on 3 Keston models in our database.

Technical description: Return thermistor open circuit - check/replace connections/thermistor

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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Keston models that show the E 37 fault code

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

Source

Keston E 37 fault code information on this page is sourced and cross-checked against the official Keston service / installation manuals for each affected model.

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