---
title: Device overview
description: "### Connections and indications ![](https://faqdoc.info/wp-content/uploads/2024/04/137332_2247_EA_AdBB_Bx1902-08N2-01.svg) 1 - Boiler connection 2 - Pump connection 3 - Protective earth connection (230 V only) 4 - Voltage supply 5 - Fuse 6 - Temperature limiter or dew point monitor 7 - Changeover heating/cooling…"
url: "https://faqdoc.info/en/systemauswahl/alpha-direct-en/alpha-direct-balance-switch-base-station-en/device-overview-2/"
updated: "2026-09-29"
category: Alpha direct Balance Switch base station
---

# Device overview

### Connections and indications

![](https://faqdoc.info/wp-content/uploads/2024/04/137332_2247_EA_AdBB_Bx1902-08N2-01.svg)

1 - Boiler connection
 2 - Pump connection
 3 - Protective earth connection (230 V only)
 4 - Voltage supply
 5 - Fuse
 6 - Temperature limiter or dew point monitor
 7 - Changeover heating/cooling
 8 - Setback temperature channel external timer
 9 - Thermostat connection
 10 - LED
 11 - NFC antenna
 12 - Connection of valve drives
 13 - Strain relief

### Technical data

| Operating voltage | 24 V ±20 %, 50 Hz, 230 V ±10 %, 50 Hz |
| --- | --- |
| Power consumption | max. 50 VA |
| Power consumption (idle) | <1 W |
| Fuse | 24 V: T2A 230 V: T4AH |
| Connectable room controllers | max. 8 |
| Connectable room controllers | A 20x05, AST 20x05, A 40x05, AST 40x05 |
| Connectable valve drives | max. 12 actuators |
| Inrush current per valve drive | 230 V: max. 500 mA |
| max. permissible nominal load of the connectable valve drives | 24 V: max. 24 W |
| **Pump connection Switching capacity** | 2 A, 200 VA induktiv |
| - Turn-on delay | parametrisable (default: 2 minutes) |
| - Follow-up time | parametrisable (default: 2 minutes) |
| **Boiler connection Switching capacity** | 2 A, 200 VA induktiv |
| - Turn-on delay | parametrisable (default: 0 parametrisable ) |
| - Follow-up time | parametrisable (default: 0 parametrisable ) |
| Pump protection | parametrisable (default: 3 days / 5 min.) |
| Valve protection | parametrisable (default: 3 days / 5 min.) |
| Valve drive operating principle | NC |
| Ambient temperature | 0 … 50 °C |
| Storage temperature / transport temperature | -20 … +70 °C |
| Ambient humidity | 5-80 %, non-condensing |
| ERP class according to EU 811/2013 | 1=1 % |
| Contamination degree | 2 |
| Rated impulse voltage | 1500 V |
| Protection class | 24 V: III 230V: II |
| Protection type: | IP20 |
| Function | Type 1 / type 1.C |
| Dimensions (H x W x D) | 90 x 326,5 x 52 mm |

### Display

| LED heating zones | green (one LED per HZ) |
| --- | --- |
| LED fuse | red |
| LED power | green / red (two-coloured) |
| LED pump | green |
| LED boiler | green |
| LED heating / cooling | green |
| LED Modbus | Flashing orange for Modbus activity |