30
7.15 - Master/slave assembly
Two units can be linked to create the master/slave assembly.
The master unit can be controlled locally, remotely or by
network commands. Master/slave assembly must be validated
in order to start the master/slave chiller operation.
All control commands to the master/slave assembly (start/
stop, setpoint selection, heating/cooling operation, load
shedding,.etc.).are.handled.by.the.unit.which.is.configured.as.
the master. The commands are transmitted automatically to
the slave unit. If the master chiller is turned off while the
master/slave function is active, then the slave chiller will be
stopped. Under certain circumstances, the slave unit may be
started.first.to.balance.the.run.times.of.the.two.units.
In the event of a communication failure between the two
units, each unit will return to an autonomous operating mode
until the fault is cleared. If the master unit is stopped due to
an alarm, the slave unit is authorised to start.
NOTE:
Master/slave assembly can be configured only by
Carrier service.
7.16 - Heat reclaim option (30XA)
Air-conditioning.system.consumes.a.significant.amount.of.
energy that leaves the system in the form of wasted heat.
Heat reclaim condenser water pump control enables to
capture the energy and convert it into a useful heat source
without decreasing the chiller plant capacity.
For.air-cooled.units.fitted.with.water.heat.reclaim.condenser,.
the option requires the installation of Reclaim SIOB board.
The heat reclaim mode can be controlled locally with the
Touch Pilot interface (RECLAIM – Reclaim mode),
remotely with the user contact or by Network command.
The heat reclaim function is active when the heat reclaim
entering water temperature is lower than the heat reclaim
setpoint. The difference between the heat reclaim entering
water temperature (RECLAIM menu) and the heat reclaim
setpoint (SETPOINT menu) determines the number of
circuits required to provide heat reclaim capacity.
Energy management option – board connections
Description
Input/Output
Connector
Type
Remarks
Occupancy override control
DI-01
J1
Digital input
If the contact is closed in Remote mode, the unit goes into the occupied mode
Demand limit switch 2
DI-02
J1
Digital input
If the contact is closed, the second capacity limit switch is active
Customer interlock
DI-03
J1
Digital input
Permits immediate unit shutdown (Remote mode only)
Ice storage
DI-04
J1
Digital input
If the contact is closed, the unit enters the ice storage mode
Space temperature
AI-01
J25
Analogue input
Active setpoint reset via space temperature control
Capacity limit control
AI-10
J9
Analogue input
Active setpoint reset via unit capacity control (4-20 mA)
Compressor A
DO-01
J2
Digital output
Output active if compressor A is operating
Compressor B
DO-02
J2
Digital output
Output active if compressor B is operating
Compressor C
DO-03
J6
Digital output
Output active if compressor C is operating
Chiller shutdown
DO-05
J23
Digital output
Output active (relay output) when the unit has completely stopped due to an alarm
Chiller in alert
DO-06
J22
Digital output
Output active (relay output) when the alert has been tripped
Unit capacity
A0-01
J10
Analogue output
0 to10 VDC output
Depending on the control mode, the Heat Reclaim option
can be enabled as follows:
Mode
Description
Local
Use the Touch Pilot user interface to set “Heat Reclaim Select”
parameter to “yes” in the Reclaim menu (Main menu).
Remote
Close the RECL_SW input (DI-02, Reclaim SIOB board).
Network
Force the RECL_SW parameter to “yes” through the CCN bus
(RECLAIM table).
Units in Master/Slave assembly
When the unit is a Slave and operating in the Master/Slave
assembly, the option is active depending on conditions given
in the table below:
Reclaim
mode
Local mode (Heat
Reclaim Select = yes)
Remote mode
(RECL_SW)
Network mode
(RECL_SEL CCN bus)
no
no
open
no
yes
yes/no
closed
yes/no
yes
yes
open
yes/no
yes
yes/no
open
yes
The heat reclaim function can be deactivated manually or
automatically when the heat reclaim entering water temperature
is higher than the heat reclaim setpoint, plus half of the heat
reclaim deadband. In the deadband the heat reclaim function
is still active.
Changeover procedure from cooling to heat reclaim mode:
1) Start-up of the condenser pump.
2)
Verification.of.the.condenser.flow.switch.control.
contact. If this remains open after one minute of the
condenser pump operation, the circuit remains in
cooling mode and an alarm will be activated.
3) As soon as delta between saturated condensing
temperature and saturated suction temperature
reaches 10°C, the pump-down sequence is activated.
4) Pump down. Opening of the water condenser water
inlet valve and closing of the air condenser air valve.
5) The heat reclaim function starts after about three minutes.
7.17 - Energy management module
The energy management module enables to control the level
of energy consumption, providing users with information
such as current unit status, compressors operating status, etc.
This option requires the installation of an additional SIOB
board.
