Technical Instructions
RCU61U Room Temperature Controller
Document Number 155-328P25
for CAV Systems
October 6, 2016
Page 4
Siemens Industry, Inc.
Operating Modes
The following operating modes are available:
Normal
When dry contact (3) is open, the setpoint knob setting takes over control and normal
mode is initiated.
Energy Saving
Energy saving mode can be initiated by activating the external operating mode
changeover switch, if DIP Switch No. 1 is set to
ON
.
In energy saving mode, the heating setpoint is 61°F (16°C) and the cooling setpoint is
82°F (28°C), independent of the position of the setpoint knob.
When the DIP switch is in energy saving mode and the fan speed control is set to
standby, the energy saving mode takes precedence over standby mode. Low fan speed
will be selected even though the fan switch is on standby.
Frost Protection
Frost protection mode can be initiated by activating the external operating mode
changeover switch, if DIP Switch No. 1 is set to
OFF
.
If the room temperature falls below 46°F (8°C), the controller will automatically switch to
frost protection mode. In that case, the heating valve opens and the room temperature
is maintained at a setpoint of 46°F (8°C). Any adjustments you make to the setpoint will
be ignored.
Operating Mode
Changeover Switch
A changeover switch can be connected to status input D1
–GND. When the switch
closes its contact (caused by an open window, for instance), the operating mode will
change from normal operation or standby to energy saving mode (if DIP Switch No. 1 is
set to
ON
), or from normal operation or energy saving mode to standby (if DIP Switch
No. 1 is set to
OFF
).
The operating action of the switch (Normally Closed - NC or Normally Open - NO) can
be selected.
Mechanical Design
The unit consists of two parts:
•
A plastic housing which accommodates the electronics, the operating elements, and
the built-in room temperature sensor.
•
A controller base.
The housing snaps into the top and bottom of the mounting base.
The screw terminals are mounted on the base. The DIP switches and the potentiometer
are located at the rear of the unit. To access the DIP switches, remove the controller
from the controller base. See Figure 5.
Figure 5. DIP Switch Settings.
