Low
d4 on Alpha E-Tec S

This code is simply showing you the current temperature setting for your radiators, rather than indicating a fault with your boiler.

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 E Tec S installation & service manual, page 33.
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 message, not an error.Observe the display as it will usually return to showing the water temperature or standby mode automatically.If you wish to change the temperature, use the heating dial or buttons on the front panel.

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