Technical Instructions
RDF20U Room Temperature Controller with LCD
Document Number 155-334
for Two-Pipe Fan Coil Units with Electric Heat
September 27, 2007
Page 6
Siemens Industry, Inc.
Operating Modes
Normal Mode
Heating or Cooling mode with automatic changeover and manually selected fan speed
(III, II or I). In Normal mode, the controller maintains the adjusted setpoint.
Economy Mode
A potential-free operating mode changeover switch can be connected to status input
D1-GND. When the switch closes its contact (due to an open window, for instance), the
operating mode will change from Normal to Economy. In this operating mode, the
relevant setpoints of heating or cooling are maintained (adjustable in Parameters P01
[setback temperature for heating] and P02 [setback temperature for cooling]). The
operating action of the switch (NC or NO) can be selected.
Standby
The relevant setpoints of heating and cooling are maintained when in Standby mode,
provided those setpoints have been adjusted. The standby temperature setting for
Heating mode in Parameter P03 is adjustable from 41°F to 68°F (5°C to 20°C) or
“OFF”
and the setting for Cooling mode in Parameter P04 is adjustable from 70°F to 95°F
(21°C to 35°C) or OFF.
Avoiding Damage Due to
Moisture (continuous
fan)
To avoid damage due to moisture in very warm and humid climates resulting from lack
of air circulation in Economy mode (for example, in hotel rooms during unoccupied
periods), the fan can be kept running in Economy mode when activating Parameter
P17. In this case, the fan keeps running at the selected speed or at speed I if the
operating mode select
or is in Standby “ ”.
Setting the Control
Parameters
A number of control parameters can be set to optimize control performance. These
parameters can also be set during operation without opening the unit. In the event of a
power failure, all set control parameters will be maintained.
Settings
The parameters can be changed as follows:
1.
Set the operating mode selector to Standby “ ”.
2. Press buttons "+" and "
–" simultaneously for a minimum of three seconds. Release
them and, within two seconds, press the "+" button again for three seconds. The
display will show P01.
3. Select the required parameter by repeatedly pressing the "+" and "
–" buttons:
4. Press buttons "+" and "
–" simultaneously; the current value of the selected
parameter appears, and can be changed by repeatedly pressing the "+" and "
–"
buttons.
5. Press buttons "+" and "
–" simultaneously again or five seconds after the last press
of a button. The last parameter will be displayed again.
6. To display and change additional parameters, repeat steps 3 through 5.
7. All changes will be stored and the controller returns to Normal operation 10
seconds after the last display or setting.
