This document introduces the RDX42 room temperature controller and heat pump system with LCD display from Siemens Building Technologies. The controller can provide single-stage or dual-stage heating, single-stage cooling, and output signals to compressor, reversing valve, switch valve actuator, auxiliary electric heating, and single-speed fan. It can control based on room or return air temperature and has normal, energy-saving, and off working modes. The controller also supports external remote control and installation parameter selection.
The RDX42 is a liquid‑crystal‑display room temperature controller designed for heat‑pump systems with reversing valves, electric heating, and single‑stage cooling. It supports both room‑temperature and return‑air temperature sensing and offers normal, energy‑saving and off modes with optional fan control.
The manual provides detailed instructions for installation, DIP‑switch configuration, parameter adjustment, wiring diagrams, calibration, environmental limits and certification data, enabling technicians to set up and maintain the controller safely and efficiently.
| Power supply voltage (230 V version) | AC 230 V ±10 %/‑15 % |
|---|---|
| Power supply voltage (24 V version) | AC 24 V ±/‑20 % |
| Frequency | 50 Hz / 60 Hz |
| Maximum power consumption | 6 VA |
| Temperature range (setpoint) | 8 °C … 35 °C |
| Control accuracy at 25 °C | ±0.5 K |
| Heating mode conversion error (adjustable) | 2 K |
| Cooling mode conversion error (adjustable) | 1 K |
The controller can be powered from AC 230 V with a ±10 %/‑15 % tolerance or from AC 24 V with a ±/‑20 % tolerance.