Siemens RDU20U, RDU50U, RDU50.2U, RDX42.22U Installation Instructions Manual

Installation Instructions

RDU… and RDX42.22U Room

Document No. 129-491

October 6, 2009

Temperature Controllers

Product Description

The RDU Series and RDX42.22U Room
Temperature Controller with LCD are designed for
heating and cooling systems.

Product Numbers

RDU20U Floating output, auto changeover
RDU50U Modulating output, auto changeover
RDU50.2U Modulating output, manual changeover
RDX42.22U On/off output, manual changeover

Required Tools

• Small, flat-blade screwdriver

• Wire strippers

• Electric drill

Expected Installation Time

30 minutes

Installation

Step 1. Loosen Retaining Screws.

Accessories:

• 141-570 Lockable Thermostat Guard

• ARG70 Wall Plate Adapter

• QAH11.1 Remote/Chan geover Sensor

Item Number 129-491, Rev. BA Page 1 of 7

Step 2. Remove Controller Housing.

Step 3. Remove Screw and Open Terminal

Cover. Remove Installation Hardware.

Document No. 129-491
Installation Instructions
October 6, 2009

Installation, Continued

Step 4. Mount Base Plate to Wall.

Step 5. Terminate Wires (See Wiring Diagrams),

Close Cover Terminal Cover and Replace Screw.

Step 6. Set DIP Switches.

Step 7. Replace Controller Housing.

Step 8. Tighten Retaining Screws.

Wiring Diagrams

Figure 1. RDU20U.

Page 2 of 7 Siemens Industry, Inc.

The installation is now complete.

1 Operating voltage, 24 Vac negati ve
2 Operating voltage, 24 Vac positiv e
3 Operating voltage, 24 Vac positiv e
4 Control signal, opening, 24 Vac
6 Control signal, closing, 24 Vac
7 Changeover, heat/cool input
8 Measuring neutral (sensors)
9 Remote temperature sensor
D1, Signal input for potential-free operating mode
GND changeover
S1 Time clock or switch
Y1 Damper or valve actuator

Wiring Diagrams, Continued

D1, Signal input for potential-

Figure 2. RDU50U

Figure 4. RDX42.22U

Four-pipe System Wiring.

Figure 3. RDU50.2U

Figure 5. RDX42.22U

Heat Pump Wiring.

Document No. 129-491

Installation Instructions

October 6, 2009

GND free operating mode changeover switch
1 0 to 10 Vdc output
2 Heat/cool changeover
sensor input
3 Measuring neutral
4 Remote temperature sensor
input
6* Operating voltage, 24 Vac
Negative
5* Ground for control signal
7 Operating voltage, 24 Vac Positive

* 5 and 6 are connected internally

D1, Signal input for potential- free
GND operating mode changeover
1,2,3 Operating voltage, 24 Vac Negative
4 Operating voltage, 24 Vac Positive
5 Cooling output, NO contact
6 Cooling output, NC contact
7 Auxiliary heating output
8 Measuring neutral remote sensor
9 Remote temperature sensor
(QAH11.1)
10 Heating output, NO contact
11 Heating output, NC contact
12 Fan output at single speed

Figure 6. Heating/Cooling for

RDU50U Only.

Siemens Industry, Inc. Page 3 of 7

Figure 7. Heating/Cooling for

RDU20U Only.

Figure 8.