Carrier SmartVu - Actuators; Terminal Block Connections

9
3.7 - Actuators
■ Electronic Expansion Valve
The electronic expansion valve (EXV) is used to adjust the
refrigerant ow. The high degree of accuracy with which the
piston is positioned provides precise control of the refrigerant
ow and suction superheat.
■ Four-way valve
This valve is used for switching the unit into the defrost mode
when necessary (see section 6.8).
■ Flow switch
For units without internal pumps, a ow switch is mounted to
ensure that the minimum ow rate required for the correct
operation and protection of the system is maintained. If the
ow switch fails, the alarm condition shuts o󰀨 the unit.
■ Water pump (optional)
The controller can regulate one external water heat exchanger
pump. See section 6.4.
■ Boiler (optional)
The boiler is activated when the operating conditions are not
suitable for thermodynamic heating or the unit is down due to
a detected failure. If there is a unit fault in the heating mode
this output authorises start-up and shutdown of a boiler.
■ Electric heaters
Electric heaters are normally used as a supplementary heating
source in the heating mode.
3.8 - Terminal block connections
Connections available at the user terminal block may vary
depending on the selected options. The following table summarizes
connections at the user terminal block.
IMPORTANT: Some contacts can be accessed only when the
unit operates in Remote mode.
Description Board Connector Remarks
On/O󰀨 Switch SIOB DI-01, 32-33
Used for the unit on/o󰀨 control (Remote mode only):
open = unit is O󰀨
closed = heating allowed
Setpoint Switch SIOB DI-02, 65-66
When the unit is under remote control, the volt-free contact is used to determine
the active setpoint (see section 6.5.1):
open = heating setpoint 1 is used
closed = heating setpoint 2 is used
Limit Switch SIOB DI-03, 73-74
Used to control demand limit:
open = 100% capacity can be used, no demand limitation is applied
closed = demand limitation applied (see section 6.3)
Flow Switch / Interlock Switch SIOB DI-05, 34-35
Used to control the pump and unit operation:
open = pump continues to run
closed = pump is stopped (unit is not allowed to start)
DHW Tank Request Switch SIOB DI-06, 63-64
Used to command the domestic hot water loop in case of DHW option:
open = DHW disabled
closed = DHW allowed
Running Relay SIOB DO-05, 37-38 Used to signal a running status (at least one compressor start)
Alarm Relay SIOB DO-06, 30-31
Used to signal an alarm:
open = inactive (no alarms active)
closed = alarm(s) active
Electrical Heat Stage #1 or
Boiler
AUX1 DO-01, 51-52
Used to control the electrical heater stage 1 or boiler:
open = electrical heater or boiler not active
closed = electrical heater or boiler active
Electrical Heat Stage #2 AUX1 DO-02, 53-54
Used to control the electrical heater stage 2:
open = output inactive, closed = output active
Electrical Heat Stage #3 AUX1 DO-03, 55-56
Used to control the electrical heater stage 3:
open = output inactive, closed = output active
Electrical Heat Stage #4 AUX1 DO-04, 57-58
Used to control the electrical heater stage 4:
open = output inactive, closed = output active
NOTE: Please refer to the electrical scheme for more
information about electrical terminal identication.
3 - HARDWARE DESCRIPTION