INSTRUCTION
NRT405F902
i
Consult documentation in all cases where this symbol
is used, in order to find out the nature of the potential
hazards and any actions to be taken
Instruction for products with software version
1.2.
Read this instruction before installation and
wiring of the product.
1
NRT405F902
Room controller for controlling fan-coil units
NRT405F902 is a room controller intended for controlling fan-coil
heaters/coolers and actuators with 0...10 V control signal. Installation
is directly on the wall or on an electrical connection box. The fan can
be set to one of three speeds.
NRT405F902 has change-over function and can be used for 2-pipe or
4-pipe systems.
For integration into a system, NRT405F902 has communication via
RS485 (Modbus or BACnet). The device can be configured using the
application NRT tool (version 1.3-1-05 or later), which can be down-
loaded from the SAUTER ITALIA SPA web site (www.sauteritalia.it).
Technical data
Supply voltage
230 V AC ±10 %, 50/60 Hz
Power consumption
< 3 W
Ambient temperature
0...50°C
Ambient humidity
Max 90 % RH
Storage temperature
-20...+70°C
Built-in temperature sensor NTC type, range 0...50°C
Inputs
Refer to connection illustrations and
table below
Outputs
Relays for fan control, 230 V AC, 3 A
AO1, AO2, 0...10 V DC
Communication
RS485: Modbus (using automatic detection/
switching) or BACnet
Modbus
8 bits, 1 or 2 stop bits. Odd, even
(FI) or no parity
Communication speed
9600, 19200, 38400 bps (Modbus and
BACnet) or 76800 bps (BACnet only)
Terminal blocks
Lift type for a maximum cable area 2.1 mm
2
Protection class
IP20
Pollution degree
2
Overvoltage category
3
Material casing
Polycarbonate, PC
Dimensions
102 x 120 x 29 mm
Installation
Place the controller in a location that has a temperature representative for
the room. A suitable location is approx. 1.6 m above floor level in a place
with unobstructed air circulation.
Depress the locking tab in the upper edge of the controller with a
screwdriver. Carefully turn the screwdriver until the bottom plate and the
electronics unit are slightly separated (see figure 1). Then
use the cutout
that becomes visible in the edge of the bottom plate to open the upper
edge completely (see figure 2). Do the same thing in the lower edge of the
controller.
Figure 1
Figure 2
Lift the electronics unit up from the bottom plate. The bottom plate with
terminals has a number of hole combinations. Select suitable holes and
fasten the bottom plate on the wall or connection box, so that the arrows
on the bottom plate point upwards. Do not tighten the screws too hard!
Disconnection
NRT405F902 should be connected to a switch or circuit breaker in
the building installation. This switch should be in close proximity to
the controller and within easy reach of the operator, and should be
marked as the disconnecting device for the equipment.
Always use the circuit breaker to disconnect the controller from the
mains supply during maintenance of the fan-coil and actuators.
Settings
Control modes
NRT405F902 can control heating and cooling in sequence or be set
to seasonal switching between heating and cooling (change-over, see
below).
Change-over function
NRT405F902 has an input for change-over that automatically sets the
output AO1 to operate with heating or cooling function. A sensor of
type PT1000 can be connected to the input and must be mounted so
that it senses the temperature on the supply pipe to the coil.
When the temperature exceeds 28°C, the output function is set to
heating and when the temperature drops below 16°C, the output is
set to cooling. As an alternative, a potential-free contact can be used.
The input function can be set to NO/NC.
To ensure satisfactory functioning when using a sensor, the system
must have continuous primary circuit circulation. When the change-
over function is not used, the input must be left disconnected.
Operating mode
There are four different operating modes. Switching between these
modes is performed locally.
Comfort:
is shown in the display. Heating and cooling have a
smaller neutral zone NZC. An occupancy detector can be connected
to the DI in order to select between Comfort and Economy. Switching
between Comfort/Economy and Off can also be done via the On/Off
button. Comfort/Economy is selected via the parameter list.
Economy (Standby):
“Standby” is shown in the display. The heat-
ing and cooling setpoints are freely adjustable. Factory settings:
heating=15°C, cooling=30°C.
Off:
The controller does not heat or cool and the fan stops (unless
mould protection has been selected, in which case the fan will still
run).
Window:
is shown in the display, the controller is off and the fan
stops (unless mould protection has been selected, in which case the
fan will still run). The window contact is connected to the DI and must
be configured.
10830A
JAN 14
EN
