Help Center – Siemens RDQ Thermostat Wiring and Terminal Mapping

Help Center – Siemens RDQ Thermostat Wiring and Terminal Mapping

The Siemens RDQ400 is designed for 2-pipe fan coil units.  Please note the wiring and terminal mapping as follows:

Main Power Terminals

• N: Neutral input (AC 230 V power supply)
• L: Line/Mains input (AC 230 V power supply) 

3-Speed Fan Control Outputs

• Q1: Fan Speed 1 Output (Low speed, AC 230 V relay)
• Q2: Fan Speed 2 Output (Medium speed, AC 230 V relay)
• Q3: Fan Speed 3 Output (High speed, AC 230 V relay) 

Control Valve Relay Outputs (SPDT)

• Y12: Valve Output – Normally Closed (NC) (AC 230 V)
• Y14: Valve Output – Normally Open (NO) (AC 230 V) 

Important Safety Warnings

• Make sure to disconnect all power supplies at the main breaker before handling or inserting any wiring.
• Double-check your physical fan coil unit label to confirm it operates on a standard AC 230V system before connection