Low
d4 on Alpha Intec 40GS2

Your boiler is notifying you that the current temperature setting for your radiators is being communicated to the system, which is a normal status indication rather than a fault.

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

From this model's manual
Verified against the Alpha Intec 40gs2 installation & service manual, page 28.
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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