3.1 Control boards
Connect Touch is the main controller that constantly monitors
the unit and manages the information received from various
pressure and temperature probes.
The control system includes the following modules:
• Connect Touch (cont user interface)
•
SIOB board that manages the major inputs and outputs of
the controller
• AUX1 board used for controlling DHW, electric heating and
others
Boards communicate via an internal bus.
3.2 Power supply to boards
All boards are supplied from a common 24 VAC supply referred
to earth. In the event of a power supply interrupt, the unit restarts
automatically without the need for an external command.
However, any faults active when the supply is interrupted are
saved and may in certain cases prevent the unit from restarting.
CAUTION: Maintain correct polarity when connecting the
power supply to the boards, otherwise the boards may be
damaged.
3.3 Light emitting diodes on boards
All boards continuously check and indicate the proper operation
of their electronic circuits. A light emitting diode (LED) lights on
each board when it is operating properly.
•
The red LED flashing for a two-second period indicates
correct operation. A different rate indicates a board or a
software failure.
•
The green LED flashes continuously on all boards to show
that the board is communicating correctly over its internal
bus. If the green LED is not flashing, this indicates the
internal bus wiring problem or a configuration issue.
3.4 Pressure transducers
The control implements three types of pressure transducers, i.e.
low pressure, high pressure, and water pressure type. The water
pressure transducer is used only in case of units fitted with the
hydronic module.
Discharge pressure transducer (high pressure type)
This transducer measures the discharge pressure in the circuit.
It is used to control condensing pressure or high pressure load
shedding. Discharge pressure sensor is mounted on the discharge
line piping of the circuit.
Suction pressure transducer (low pressure type)
This transducer measures the suction pressure in the circuit.
It is used to control EXV, evaporating pressure (in heating
mode) and monitor suction pressure safeties related to the
compressor operating envelope. Suction pressure sensor is
located on the suction piping of the circuit.
Economizer pressure transducer
(high pressure type)
This sensor measures the intermediary pressure between
suction and discharge pressure sensors. It is used for EXV
economizer control. The sensor is mounted on the plate
exchanger on the economizer side.
Water pressure transducer
As an option (hydronic module), this sensor is used to monitor
the water pressure. The pump is protected against cavitation
(low pump entering pressure).
3.5 Temperature sensors
Temperature sensors constantly measure the temperature of
various components of the unit, ensuring the correct operation
of the system.
Water heat exchanger entering and leaving water
temperature sensors
The water heat exchanger entering and leaving water temperature
sensors are used for capacity control and safety purposes.
The water temperature sensors are installed in the entering and
leaving side.
Suction temperature sensors
Suction temperature sensors are used to control temperature
at the compressor inlet line in order to ensure correct capacity
control management.
Economizer suction temperature sensor
This sensor is used for economizer EXV control. The sensor
measures the temperature of gas in the plate exchanger on
economizer side before entering the compressor economizer port.
Outdoor air temperature sensor
This sensor measures the outdoor air temperature used to
determine the summer mode (see section 7.6.3) or calculate
the control point provided that the offset (reset) is based on the
outdoor air temperature reading (see section
Defrost temperature sensors
These sensors are used to determine the end of the defrost cycle
for a circuit. Units with two fans have two defrost sensors, one
sensor per each fan.
Domestic hot water temperature sensor (optional)
This sensor is used to measure the water tank temperature and
control the heating request.
Master/Slave water sensors (optional)
These sensors measure the common water temperature in the
master/slave system capacity control. They are installed only in
the case of master/slave units.
3.6 Actuators
Electronic Expansion Valve
The electronic expansion valve (EXV) is used to adjust the
refrigerant flow. The high degree of accuracy with which
the piston is positioned provides precise control of the refrigerant
flow and suction superheat.
Four-way valve
This valve is used for switching the unit into the defrost mode
when necessary. See section 7.8
Flow switch
For units without internal pumps, a flow switch is mounted
to ensure that the minimum flow rate required for the correct
operation and protection of the system is maintained. If the flow
switch fails, the alarm condition shuts off the unit.
Water pump (optional)
The controller can regulate one external water heat exchanger
pump. See section
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 - HARDWARE DESCRIPTION
EN - 3
AQUACIAT
CALEO
