BoilerFaultCodesAlpha 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 24 Alpha models in our database.
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.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Alpha models that show the 37 fault code
Click a model for the full fault code list and model-specific repair notes.
- C25 Xtraflame Repair: £120-250
- E-Tec Repair: £120-250
- E-Tec 24 Repair: £120-250
- E-Tec 28 Repair: £120-250
- E-Tec 33 Repair: £120-250
- E-Tec Plus Repair: £120-250
- E-Tec Plus 10 / 18 Repair: £0-180
- E-Tec Plus 24 Repair: £120-250
- E-Tec Plus 28 Repair: £120-250
- E-Tec Plus 33 Repair: £120-250
- E-Tec R Repair: £120-250
- E-Tec Regular Repair: £100-350
- Eco Repair: £120-250
- Eco 11 13 Repair: £100-280
- Evoke Repair: £100-250
- Evoke 10 / 18 Repair: £100-350
- FMK Repair: £0-120
- H25 Xtraflame Repair: £120-250
- Intec 24GS Repair: £100-250
- Intec 28GS Repair: £120-250
- Intec 40GS2 Repair: £120-250
- Intec 50CS Repair: £120-250
- Intec2 25 28XE Repair: £120-250
- Intec2 30SE Repair: £120-250
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 27 April 2026