Low
d3 on Alpha Eco

Your boiler is simply displaying the current temperature of the hot water as it leaves the unit, rather than an active 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

Domestic hot water temperature leaving the boiler °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.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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