E15 Low

Warmflow E15 Fault Code

The Warmflow E15 fault code means: your boiler's internal sensor that monitors the temperature of the water returning from your radiators has developed a fault or become disconnected.. It appears on 3 Warmflow models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: CH Return NTC Error — CH return NTC temperature sensor short circuit or disconnected (logged only, not shown on LCD); consult Service Engineer
Typical repair cost £90-160 (including labour)

Engineer required

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

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Warmflow models that show the E15 fault code

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

Source

Warmflow E15 fault code information on this page is sourced and cross-checked against the official Warmflow service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026