Nibe SPLIT HBS 12 Installation And Maintenance Instructions Manual page 42

For the Installer
Electrical installation
2. Connect the addition's phase to terminal block X3:2
(230 V) and X3:4 (N) (max 0.2 A).
3. Use the accessory HR10 when the need for potential
for signal and/or when controlling external charge
pumps.
4. Set "Ext. 1 step" in menu 9.2.8.
38 NIBE™ SPLIT