Medium
ALL 04 on Sime Murelle EV HE 25 Combi

Your boiler is having trouble reading the temperature of your hot water, which means it will still supply hot water but you may not be able to control how hot it gets.

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

D.H.W. SENSOR ALARM 04: If the D.H.W. sensor (SS) is open or short circuit, the boiler will continue to operate but without control of the D.H.W. temperature.

From this model's manual
Verified against the Sime/Sime Murelle Ev He Combi 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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Related fault codes

ALL 01View →ALL 03View →ALL 05View →

All 22 fault codes on the Murelle EV HE 25 Combi

Seeing a different code? Every code this model can display, in one place.

ALL 02ALL 03ALL 05ALL 06ALL 07ALL 08ALL 09ALL 14ALL 15ALL 20ALL 21ALL 22ALL 23ALL 24ALL 25ALL 26ALL 27ALL 28ALL 29ERROR 10ERROR 13

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