Medium
ALARM 04 on Sime Murelle HE System

Your boiler has a fault with the domestic hot water sensor, meaning it may still provide heating but cannot accurately control the temperature of your hot water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

DHW sensor (SS) fault — open or short circuit; boiler continues but without DHW temperature control; check/replace sensor

From this model's manual
Verified against the Sime Murelle He System installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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ALARM 05View →ALARM 06View →

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