1.1.3
Keypad and Display
User interface is via a touch keypad and a liquid crystal
display allowing access to operating and programmed
data. Information can be displayed in S.I. (Metric) or
Imperial units. The 40 character liquid crystal display (2
lines of 20 characters) is used for displaying system
parameters and operator messages. The display has a
lighted background for night viewing as well as a special
feature which intensifies the display for viewing in direct
sunlight.
1.1.4
Unit (Chiller) ON/OFF Switch
The unit ON/OFF switch is located just below the
keypad. This switch allows the operator to turn the entire
chiller OFF, if desired. The switch must be placed in the
ON position for the chiller to operate. Any time the switch
is in the OFF position, a STATUS message will be
displayed.
1.1.5
Customer Controls
The microprocessor based control system can accept
remote signals to start and stop the chiller, to adjust the
leaving liquid temperature setpoint and to load limit the
unit. To reduce unit noise on YLAA and YLAE units with
the 2 speed fan option, a customer voltage free contact
can be connected to inhibit fan full speed .These
functions can easily be controlled by connecting user
supplied voltage free contacts to the customer terminals
in the electronics section of the control panel.
In addition, run status and alarm contacts are provided
to remotely signal system status and faults.
SYSTEM INPUTS
Wiring from remote voltage free contacts
should be run in screened cable earthed at the
panel end only. If an inductive device (relay,
contactor) is supplying these contacts, the coil
of the device must be suppressed with a
standard RC suppresser across the inductive
coil.
1.1.6
Remote Start/Stop
Remote start/stop can be accomplished using a time
clock, manual contact or other voltage free contact
connected to terminals 13 and 14 (-ARB circuit board on
YLAA and YLAE units) or 13 and 51 (-XTBC1 on
YCWL/YCRL units). The contact must be closed to
allow the chiller to run. Any time the contact opens for
more than 3 seconds, the chiller will shutdown and the
'REMOTE STOP NO RUN PERM' message will be
displayed.
1.1.7
Flow Switch
(YCWL/YCRL and YLAA / YLAE
units without the hydro kit option)
The customer must install and wire a field mounted flow
switch. The flow switch should be rated for 30 Vdc 1 to 3
ma, gold contacts recommended, connected to
terminals 13 and 18 (-ARB circuit board on YLAA and
YLAE units) and 13 and 14 (-XTBC1 on YCWL/YCRL
units) to provide adequate protection against loss of
liquid flow.
The flow switch should never be by-passed.
This will cause damage to the chiller and
invalidate the warranty.
The optional Hydro Kit is fitted with a flow switch.
1.1.8
EMS PWM Remote Setpoint Reset
(Activated on request)
The leaving liquid temperature setpoint programmed
into the microprocessor can be remotely adjusted to a
higher value using repeated timed closure of voltage
free contacts 13 and 20 (-ARB circuit board on YLAA
and YLAE units) and 13 and 20 (-XTBC1 on
YCWL/YCRL units). The duration of the contact closure
will decide the amount of adjustment.
For noise immunity, the microprocessor will ignore
closures of less than 1 second.
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Form 201.26.OI1(11/09)
