Low
Orange LED on on Sime Format B Combi

Your boiler is in normal standby mode and is waiting for a command to provide heating or hot water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Stand-by / off — normal stand-by condition

From this model's manual
Verified against the P3 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.

DIY fix possible

Ensure your room thermostat is turned up high enough to call for heatCheck that your heating timer or programmer is set to 'ON'Turn on a hot water tap to see if the light changes to green and the boiler fires up

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Related fault codes

Green LED onView →Red LED onView →

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