Low
d4 on Alpha Eco 11 13

Your boiler is simply displaying the current target temperature setting for your radiators, and there is no actual fault with the appliance.

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

Central heating set point temperature °C

From this model's manual
Verified against the Alpha Eco installation & service manual, page 23.
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

This is a status indicator rather than a fault codePress the reset button if the boiler is unresponsiveCheck your radiator dial settings to ensure they are at your desired comfort level

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