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3 - HARDWARE DESCRIPTION
3.1 - Control boards
The control system consists of the main controller, i.e. Touch
Pilot Junior, and at least one SIOB board. The controller
constantly monitors the unit and manages the information
received from various pressure and temperature probes.
The electrical box includes all boards controlling the unit and
the user interface. All boards communicate via an internal bus.
The number of SIOB boards depends on the following:
•
Size of the unit:
Single-circuit units have one SIOB
board.by.default,.whereas.dual-circuit.units.are.fitted.
with two SIOB boards (the second SIOB board is
normally used to support the second refrigerant circuit).
•
Additional options:
.20.to.140.units.may.be.fitted.with.
the second SIOB board only if the unit comes with
additional functionalities, e.g. pump on the source side
(condenser pump or cooler pump), partial heat recovery
option, i.e. desupeheater (scheduled for future release).
In addition to SIOB board(s), 30WG / 30WGA / 61WG units
of all sizes can be equipped with AUX1 board(s). The number
of AUX1 boards installed on the unit depends on the selected
options (see below).
AU
X1 boar
d
Option
30WG
30WGA
61WG
Domestic Hot Water (DHW)
o
o
Master/Slave assembly
o
o
o
Brine to water
o
Free cooling dry cooler*
o
o
Dry cooler (condenser)*
o
o
*For these two options the board is directly installed in the dry cooler itself, not in
the control box of the air-conditioning unit.
3.2 - Power supply to boards
All boards are supplied from a common 24 VAC supply
referred to earth.
CAUTION:
Maintain correct polarity when connecting the power supply
to the boards, otherwise the boards may be damaged.
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 a given circuit or
the unit from restarting.
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.on.the.
SIOB board 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 a LEN bus wiring problem.
3.4 - Pressure transducers
The control implements three types of pressure transducers,
where two pressure transducers (high pressure and low
pressure) are used to measure the suction and discharge pressure
in each circuit and the third transducer type is water pressure
type.used.in.case.of.units.fitted.with.the.hydronic.kit.option.
Discharge pressure transducers (high pressure type)
These transducers measure the discharge pressure in each
circuit. They are used to control head pressure or high
pressure load shedding. Discharge pressure sensors are
mounted on the discharge line piping of each circuit.
Suction pressure sensors (low pressure type)
These transducers measure the suction pressure in each circuit.
They are used to control EXV, evaporating pressure (in
heating mode) and monitor suction pressure safeties related
to the compressor operating envelope. Suction pressure
sensors are located on the suction piping of each circuit.
Water pressure transducers
As an option (hydronic kit option), these sensors are used to
monitor.the.water.pressure.and.the.water.flow.by.measuring.
the.water.pressure.in.two.different.locations..The.water.flow.
rate.is.calculated,.the.unit.is.protected.against.water.flow.losses.
and 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 temp. sensors
The water heat exchanger entering and leaving water temp.
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.
Condenser entering and leaving water temp. sensors
(30WG/61WG)
The condenser entering and leaving water temperature sensors
are used for heating capacity control and safety purposes.
Outdoor air temperature sensor (optional)
If available (30WG/61WG with DHW option, 30WGA as
standard), this sensor measuring the outdoor air temperature is
used for the reset signal calculation and for condensing fan
control (standard for dry cooler and condenserless unit control).
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.
