Siemens RDX42.22U Owner's manual

RDX42.22U
Technical Instructions
Document No. 155-747
March 13, 2008
Room Temperature Controller
with LCD
Siemens Industry, Inc.
Description Controller for heat pump systems with reversing valve, optional electric heater, one- or
two-stage heating and one-stage cooling.
Features •Outputs for one-stage compressor and reversing valve or on/off valve actuators
•Output for auxiliary electric heating
•Output for a one-speed fan
•Room or return air temperature control
•Manual heating/cooling changeover
•Operating modes: Normal (heating, cooling), Energy Saving, Off
•Operating mode changeover input for remote control
•Selectable installation and control parameters
•Operating voltage 24 Vac
Application •For control of heat pump systems with reversing valve, optional electric heater, one-
or two-stage heating and one-stage cooling
•For control of room temperature in individual rooms that are heated or cooled with
four-pipe fan coil units and optional electric heating
•For opening and closing a valve
•For switching a one-speed fan
Product Number RDX42.22U
Accessories ARG70 Adapter Plate for 4 × 4-inch conduit boxes
QAH11.1 Changeover/Remote Temperature Sensor
141-570 Lockable Thermostat Guard
Ordering The QAH11.1 temperature sensor (can also be used as a return air temperature
sensor) and the zone valves must be ordered separately.

Technical Instructions RDX42.22U Room Temperature Controller with LCD
Document Number 155-747
March 13, 2008
Page 2 Siemens Industry, Inc.
Table 1Equipment Combinations.
Product Number Description Technical
Instructions
SFA/SFP Series
Zone valve actuators
155-321P25
599 Series Zone Valves
Zone valve bodies
155-320P25
GDE16… 44 lb-in NSR air damper
actuators
155-187P25
GLB16… 88 lb-in NSR air damper
actuators
155-187P25
Temperature Sensor QAH11.1 155-329P25
Functions The controller acquires the room temperature with its integrated sensor or via a return
air temperature sensor (QAH11.1) and maintains the setpoint by delivering two-position
control commands. The switching differential is 4°F (2°K) in heating mode (adjustable)
and 2°F (1°K) in cooling mode (adjustable).
Fan Operation Fan operation is selected on the controller’s front panel, either in "Auto” or “Fan On”
mode.
When function "(Auto) – temperature-dependent" is selected, the fan is switched on/off
(one-speed) depending on the temperature and the control output. When function “Fan
On” is selected, the fan will run continuously (one-speed).
The fan is switched off by:
•leaving the heating or cooling sequence, if the “Temperature-dependent fan control“
function is activated.
•manually setting the “Heat-Off-Cool” selector to “Off”.
•turning the controller’s power supply off.
Fan overrun When DIP switch 2 is set to OFF, the auxiliary heater is connected, the controller is in
heating mode, and the fan overrun function is activated. When the electric heater
output (terminal 7) is switched off by the controller in the heating sequence, the fan
overrun will start based on the time delay set with parameter P08. Fan overrun has the
highest priority and overrides the controller’s Off position.

RDX42.22U Room Temperature Controller with LCD Technical Instructions
Document Number 155-747
March 13, 2008
Siemens Industry, Inc. Page 3
Heating Mode The system will switch to Heating mode when the operating mode selector, on the front
of the unit, is set to Heat.
On
The heating equipment receives the On command via control output terminal 10 when
the following conditions are met:
1. The measured room temperature is half the switching differential below the
setpoint, and
2. The heating output has been off for more than three minutes (adjustable).
The auxiliary heating equipment receives the On command via control output terminal 7
when these conditions exist:
1. Heating output terminal 10 is activated, and
2. The measured room temperature is below the setpoint differential between heating
and auxiliary heating(adjustable with parameter P12).
Off
The heating equipment receives the Off command via control output terminal 10 when
the following conditions are met:
1. The measured room temperature is half the switching differential above the setpoint,
and
2. The heating output has been on for more than one minute (adjustable, see
Parameters).
The auxiliary heating equipment receives the off command via control output terminal 7
when:
1. The measured room temperature is above the setpoint differential between
heating and auxiliary heating (WD) (adjustable with parameters P12), and
2. The auxiliary heating output has been on for more than one minute (adjustable, see
Parameters).
Cooling Mode
On
When the operating mode selector is set to Cool, the system will switch to cooling
mode.
The cooling equipment receives the On command via control output terminal 5 when
the following conditions occur:
1. The measured room temperature is half the switching differential above the
setpoint, and
2. The cooling output has been off for more than three minutes (adjustable, see
Parameters.)
Off The cooling equipment receives the Off command via control output terminal 5 when
these conditions are met:
1. The measured room temperature is half the switching differential below the setpoint,
and
2. The cooling output has been on for more than one minute (adjustable, see
Parameters).
Return air temperature
The RDX42.22U provides control based on room temperature or return air temperature.
It detects if a QAH11.1 cable temperature sensor is connected to input terminals 9 and
8, and then operates automatically according to the return air temperature.

Technical Instructions RDX42.22U Room Temperature Controller with LCD
Document Number 155-747
March 13, 2008
Page 4 Siemens Industry, Inc.
Operating Modes
Normal
The following operating modes are available:
Heating or cooling mode with selected fan operation (Auto or continuous on). In Normal
operation, the controller maintains the adjusted setpoint. (See Operation Diagram).
Energy Saving A changeover switch can be connected to status input D1-GND, located on the lower
left side of the base plate, below the main terminal block. When the switch closes (due
to an open window, for example), the operating mode will change from Normal
operation to Energy Saving mode. In that case, the relevant setpoints of heating or
cooling are maintained (setting of control parameters P01 and P02). The operating
action of the switch (NC or NO) can be selected.
Off When the operating mode selector is set to Off, the system will switch to Off mode. In
this mode, the system does not activate any output. The display only shows the room
temperature, or normal mode setpoint, according to the DIP switch setting table.
After a single press of the +or –button, the display shows the Normal mode setpoint.
When the operating mode selector is set to Off, the system will stay in Off mode.
Operation Diagrams
(Normal Mode)
NOTE: Changed
"Actuator" to "Valve" in
illustration.
Figure 1. Operation Diagrams.
Mechanical Design The unit consists of two parts:
•The plastic housing which accommodates the electronics, the operating elements
and the built-in room temperature sensor, and
•The baseplate, which houses the wire terminations.
The housing engages in the baseplate and is secured with two screws.
The baseplate carries the screw terminals. The DIP switches are located at the rear of
the housing.

RDX42.22U Room Temperature Controller with LCD Technical Instructions
Document Number 155-747
March 13, 2008
Siemens Industry, Inc. Page 5
Setting and
Operating Elements
Figure 2.
1. Display of the room temperature (in degrees Fahrenheit or Celsius), setpoints or
control parameters
2. Symbol used when displaying the current room temperature
3. Normal operation
4. Energy Saving mode
5. Cooling on
6. Fan on
7. Heating on
Heating and auxiliary heating on
AUX
8. Buttons for adjusting the setpoints and setting the control parameters
9. Operating mode selector (Heat, Off, Cool)
10. Fan control
(Auto: Controller switches fan on when heating or cooling output is active)
(Fan On: Fan is constantly running)
Table 2. DIP Switch Table.
DIP
Switch Function Position OFF Position ON
1 Operating action of remote
ON/OFF switch Changeover activated when switch is open (NC) Changeover activated when switch is closed (NO) *
2 Auxiliary heating function Auxiliary heater connected No auxiliary heater connected *
3 Temperature/setpoint display Temperature setpoint Room temperature *
4 Temperature display Degrees Fahrenheit * Degrees Celsius
* Factory setting

Technical Instructions RDX42.22U Room Temperature Controller with LCD
Document Number 155-747
March 13, 2008
Page 6 Siemens Industry, Inc.
Setting the
Control
Parameters
A number of control parameters can be set to optimize the control performance. These
parameters can also be set during operation without opening the unit. In the event of
power failure, all control parameter settings set will be maintained.
Settings The parameters can be changed as follows;
1. Press the +and –buttons simultaneously for three seconds. Release them and,
within two seconds, press the +button again for three seconds. Then, the display
will show “P01“.
2. Select the required parameter by repeatedly pressing the + and - buttons:
006_RDX42_01
P01 P02 P13 P14
+- +-+
- -
+
3. By pressing the + and – buttons simultaneously, the current value of the selected
parameter appears, which can be changed by repeatedly pressing the + and –
buttons. To exit from the individual parameter setting mode, press the + and –
buttons simultaneously again and the parameter mode setting number will be
displayed “Pxx”. You can now choose another parameter mode number setting.
4. By pressing the + and – buttons simultaneously again, or five seconds after the last
press of a button, the last parameter will be displayed again.
5. If you wish to display and change additional parameters, repeat steps 2 through 4.
6. Wait 10 seconds after the last display or setting, all changes are stored and the
controller returns to Normal mode.
P13 and P14
(Display only, no
setting)
P13 shows the room temperature and the sensor being used by the device to calculate the
output.
P14 displays the current value of the temperature sensor connected.
1: Internal sensor
2: External sensor. No settings
If the position of the operating mode selector or remote ON/OFF switch is changed in this
parameter setting mode, the device will abort the setting mode and respond to the new
input after 10 seconds. The data changes are saved.

RDX42.22U Room Temperature Controller with LCD Technical Instructions
Document Number 155-747
March 13, 2008
Siemens Industry, Inc. Page 7
Table 3. Control Parameters.
Parameter Meaning Setting Range Factory
Setting
P01 Heating setpoint in Energy Saving
mode (operating mode changeover
switch activated)
OFF, 46°F to 64.5°F (8°C to 18°C) (in
increments of 1°F) 61°F (16°C)
P02 Cooling setpoint in Energy Saving
mode (operating mode changeover
switch activated)
OFF, 75°F to 95°F (24°C to 35°C) (in
increments of 1°F) 82.5°F
(28°C)
P03 Minimum setpoint in Normal mode 46°F to 68°F (8°C to 20°C) (in
increments of 2°F) 46°F (8°C)
P04 Maximum setpoint in Normal mode 70°F to 95°F (21°C to 35°C) (in
increments of 2°F) 95°F (35°C)
P05 Minimum compressor off-time 1 to 10 minutes (in increments of
1 min) 3 min
P06 Minimum compressor on-time 1 to 10 minutes (in increments of
1 min) 1 min
P07 Auxiliary heater minimum hold time 1 to 10 minutes (in increments of
1 min) 1 min
P08 Fan overrun after auxiliary heater off 30 to 300 seconds (in increments of
10 seconds) 30 s.
P09 Sensor calibration –3 to 3 K (in increments of 0.5 K)
(0.5 K = °F) 0 K
P10 Switching differential in heating mode 0.5 to 4 K (in increments of 0.5 K)
(0.5 K = °F) 2 K
P11 Switching differential in cooling mode 0.5 to 4 K (in increments of 0.5 K)
(0.5 K = °F) 1 K
P12 Setpoint differential between heating
and auxiliary heating WD0.5 to 5 K (in increments of 0.5 K)
(0.5 K = °F) 2 K
P13 Value of current room temperature No setting, display only —
P14 Active temperature sensor (display
only, no setting choices) 1: Room temperature sensor active
2: Return temperature sensor active —

Technical Instructions RDX42.22U Room Temperature Controller with LCD
Document Number 155-747
March 13, 2008
Page 8 Siemens Industry, Inc.
Mounting,
Installation and
Commissioning
Notes
•Check the position of the DIP switches and change them, if necessary.
•After applying power, the controller makes a reset, which takes approximately three
seconds; it is then ready to operate.
•Mount the unit on a wall of the room to be heated or cooled. Do not mount in direct
sunlight or near other heat or refrigeration sources. (See Figure 3.)
•Mounting height is approximately 60 inches (150 cm) above the floor.
(See Figure 3.)
•The connecting wires can be run to the controller from a recessed conduit box.
Figure 3. Acceptable Mounting Locations.
•The cables used must satisfy the insulation requirements for 24 Vac potential.
•To access the wire terminal block, loosen the cover screw and open the plastic cover.
See Figure 4.
Figure 4. Accessing the Wire Terminal Block.
•Sensor inputs 9-8 carry 24 Vac potential. If the sensor's cables must be extended, they
must be suited for 24 Vac voltage.
•Complete installation instructions are included with the controller.
Calibrating the
Sensor If the room temperature displayed by the controller is inconsistent with the room
temperature effectively measured, the temperature sensor can be recalibrated. In that
case, parameter P09 must be changed.

RDX42.22U Room Temperature Controller with LCD Technical Instructions
Document Number 155-747
March 13, 2008
Siemens Industry, Inc. Page 9
Specifications
Power Supply
Operating voltage 24 Vac + 20%
Frequency 50/60 Hz
Power consumption Maximum 6 VA
Control output FAN 24 Vac
Rating Maximum 5(3)A
Control outputs COOLING and HEATING 24 Vac
Rating Maximum 5(3)A
Control output AUX. HEATING 24 Vac
Rating Maximum 5(3)A
Remote temperature sensor status input 8-7 QAH11.1 safety class II
NTC resistor 3 k ohm at 77°F (25°C)
Status input D1 and GND
Operating action selectable Normal open (NO)
Contact sensing Normal closed (NC)
Insulation against line voltage SELV 6 to 15 Vdc/3 to 6 mA, 4kV
reinforced insulation
Permissible cable length with copper cable 262 ft (80 m)
2 × 16 AWG or 1 × 14 AWG for connection to
terminals 8 and D1
Operational data
Setpoint setting range 46°F to 95°F (8°C to 35°C)
Control deviation at 77°F (25°C) Maximum + 1°F (0.5 K)
Setting Range Factory Setting
Switching differential in heating mode (adj) 1°F to 7°F 3.5°F (2 K)
Switching differential in cooling mode (adj) 1°F to 7°F 2°F (1 K)
Setpoint differential WD(adjustable) 1°F to 9°F 3.5°F (2 K)
Setpoint (Energy Saving Mode ), heating 46°F to 64°F 61°(16°C)
Setpoint (Energy Saving Mode ), cooling 75°F to 95°F 82.5°F (28°C)
Environmental
Conditions
Operation
Temperature 32°F to 122°F (0°C to 50°C)
Humidity <95% rh
Shipping and storage
Temperature –13°F to 158°F (–25°C to 70°C)
Humidity <95% rh
Agency Approvals
Conforms to CE requirements
NEMA 1
General Connection terminals Use solid wires or prepared stranded
wires. 22 AWG to 14 AWG
Weight 0.5 lb (0.225 kg)
Housing cover color White

Technical Instructions RDX42.22U Room Temperature Controller with LCD
Document Number 155-747
March 13, 2008
Page 10 Siemens Industry, Inc.
Wiring Terminals
Figure 5. Wiring.
1,2,3 Operating voltage, 24 Vac Neg
4 Operating voltage, 24 Vac Pos
5 Cooling output, NO contact
6 Cooling output, NC contact
7 Auxiliary heating output
8Measuring 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
D1, GND Signal input for potential- free
operating mode changeover
Wiring Diagrams
Figure 6. Four-pipe System Wiring.
Figure 7. Heat Pump Wiring.
6 Cooling output NC contact
5 Cooling output NO contact
11 Heating output NC contact
10 Heating output NO contact
6 Cooling output NC contact for
reversing valve
5 Cooling output NO contact for
compressor
11 Heating output NC contact for
reversing valve
10 Heating output NO contact for
compressor
NOTE: Outputs 5 and 10 must be wired
together for compressor control

RDX42.22U Room Temperature Controller with LCD Technical Instructions
Document Number 155-747
March 13, 2008
Information in this publication is based on current specifications. The company reserves the right to make changes in specifications and models as
design improvements are introduced. Product or company names mentioned herein may be the trademarks of their respective owners.
© 2008 Siemens Industry, Inc.
Siemens Industry, Inc.
Building Technologies Division
1000 Deerfield Parkway
Buffalo Grove, IL 60089
+ 1 847-215-1000
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Document No. 155-747
Printed in the USA
Page 11
Dimensions
Figure 8. RDX42.22U Dimensions in Inches (mm).