30
8.12 - Condensing pressure control (optional)
30WG/61WG units can control a dry cooler to cool down
the condenser water loop while 30WGA units can control
an air condenser. These air exchangers include all compatible
control electronics.
8.12.1 - 30WG/61WG units
The.control.can.regulate.the.following.configurations:
•
Dry.cooler.and.variable-speed.condenser.pump..The.fixed.
fan stages and the pump speed are controlled to maintain
a.fixed.condensing.setpoint.(value.adjustable).
• Variable-speed condenser pump (without dry cooler
control). The condenser pump integrated into the unit
is.controlled.to.maintain.a.fixed.condensing.setpoint.
(value adjustable).
•
Dry.cooler.and.three-way.valves..The.fixed.fan.stages.
and the three-way valve position are controlled to permit
start-ups at low outside temperatures and maintaining a
fixed.condensing.setpoint.(value.adjustable).
• Three-way valve only (without dry cooler control). The
position of the three-way valve is controlled to
maintain.a.fixed.condensing.setpoint.(value.adjustable).
•
Dry.cooler.only.(fixed.or.variable.speed)..Only.the.dry.
cooler.fan.stages.are.controlled.by.reference.to.a.fixed.
dry cooler water outlet (value adjustable).
8.12.2 - 30WGA units
30WGA units have been specially designed to optimise the
operation of split installations, using air-cooled condensers
as the heat rejection system.
The.control.configuration.of.the.air-cooled.condenser.must.
be.done.by.a.specially.trained.and.qualified.engineer.during.
the.unit.installation..Carrier.supplies.specific.documentation.
for this operation to the trained engineers.
The Touch Pilot Junior control system of 30WGA includes
logic.to.permit.control.the.different.fixed.and.variable-speed.
fan variants. Touch Pilot Junior continuously optimises system
operation.to.obtain.the.best.system.efficiency.by.controlling.
the number of fans required for any thermal load and outside
temperature conditions.
8.12.3 - Condensing setpoint
The condensing setpoint is adjustable in the Setpoint menu
(SETPOINT).
The condensing setpoint can be reset by reference to the outside
temperature to optimise the operation of the condensing system.
Condensing
control point
Minimum value
Default value Maximum value
30WG/61WG
30°C
40°C
58°C
30WGA
40°C
45°C
55°C
To set the condensing setpoint reset, the following
adjustments are necessary:
• hr_sel (Heating Reset Select) set to “1” (OAT) in the
Heat/Cool.Config.menu.(HCCONFIG).
• oathr_no (OAT no reset value), oathr_fu (OAT full reset
value) and hr_deg (heating re set deg. value) must be set
in.the.Reset.Configuration.menu.(RESETCFG)..See.also.
section 8.5.2 for more information about reset control.
8.13 - Master / Slave control
The control system allows for master/slave control of two
units linked by the network. The master unit can be controlled
locally, remotely or by network commands, while the slave
unit remains in Network mode.
All control commands to the master/slave assembly (start/
stop, setpoint selection, heating/cooling control, 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 unit is turned off, while the master/slave function
is active, then the slave unit will be stopped. Under certain
circumstances,.the.slave.unit.may.be.started.first.to.ensure.that.
the run times of the two units are equalised.
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.
IMPORTANT:
Master/slave assembly can be configured
only by Carrier service.
