37 High

Alpha 37 Fault Code

The Alpha 37 fault code means: your boiler has stopped working because the electricity supply coming into the unit has dropped below the minimum level required to operate safely.. It appears on 23 Alpha models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Low supply voltage

What causes the Alpha 37 fault?

This fault occurs when the electrical current entering the boiler drops below 175V, which is too low for the internal components to function. It is usually caused by a temporary fluctuation in the local power grid or an issue with the electrical wiring leading to the boiler. In some cases, a failing main control board inside the unit can also incorrectly detect a voltage drop that isn't actually there.

Typical repair cost £100-350 (including labour)

Engineer required

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

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Alpha models that show the 37 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Alpha 37 fault code information on this page is sourced and cross-checked against the official Alpha service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026