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Programming Functions
SERVICE FUNCTION
-
The service function allows
the operator to verify factory configurations and read
or change field configurations. The service subfunctions
are listed below. (See Table 6 for details.)
The operator must use this subfunction to
and
log on before performing
to log off after completing
any other subfunction,
service subfunctions.
If single
set point or inactive
sched ule has been
selected
in the schedule function,
then
when
+
is depressed
ii
will
show the
modified chilled water
the display
set point.
c. The modified chilled water set point is determined by
the microprocessor as a result of the reset function,
and is displayed for reference only; it cannot be set
or changed by the operator. If reset is not in effect, the
modified set point will be the same as either the occu-
pied or unoccupied chilled water set point, according
to how the schedule function has been programmed.
Displays the reset, reset Limits, and reset
pJ@-
Used to verify software version and
language option.
Used to verify factory configurations
ratio
reset
funct
set points, These set points are not accessible when
type has been configured for NONE in the service
ion.
il
---
SET
Displays the demand limit set points.
Displays time of day and day of week.
(number of compressors).
pq
m
.-..
Usrd to read or change field configuration
for number of unloaders and reset type and to enable the
machine for load shed, pulldown, or brine operation.
NOTE: The
n
f
key is used to enable or turn on certain
cl
3
0
4
functions; the
cl
I
key is used to disable thesefunctions.
key is pressed the display will show 00.00.
SCHEDULE FUNCTION
~
This function provides a
means to automaticafly switch the chiller from an
occupied mode to an unoccupied mode. When using the
schedule function, the chilled water pump relay, located
in the unit control box, must be used to switch the chilled
water pump on and off. The chilled water pump relay will
start the chilled water pump but the compressors will not
run until the remote chilled water pump interlock con-
tacts are closed and the leaving chilled water temperature
is above set point. If a remote chilled water pump inter-
lock is not used. the first compressor will start (upon a
call
for cooling) approximately one minute after the
chilled water pump is turned on.
The schedule
function can be programmed
ngle
set point. or
dual
set
pntnt
operation.
for
inactive,
si
SET POINT FUNCTION -- Set points are entered
through the keyboard. Set points can be changed within
the upper and lower limits, which are fixed. The ranges
are listed below.
Chilled
Water Set Point
Water:
40
to 70 F (4.4 to 21 C)
Brine (Special Order Units):
15
to
70
F (-9.4 to 21 C)
Rc~set
Set Point
0 to
95 F (-17.8 to 35 C)
Reset Limit
0
to
80 F (-17.8 to 26.7 C)
Reset Ratio
0 to 100%
When the schedule is configured for inactive, the
chilled water pump relay remains energized continuously
but is not used since the chiller is usually controlled by
remote chilled water pump interlock contacts.
When the schedule is set for single set point operation,
the
chilled
water pump relay will be energized whenever
the chiller is in the occupied mode regardless of whether
the chiller is running. When the chiller is in unoccupied
mode, the chilled water pump relay will not be energized.
When the schedule is set for dual set point, the chilled
water pump relay will be energized continuously, in both
occupied and unoccupied modes. The occupied mode
places the occupied chilled water set point into effect; the
unoccupied mode places the unoccupied chiller water set
point into effect.
The schedule consists of from one to 8 occupied time
periods, set by the operator. These time periods can be
flagged to be in effect or not in effect on each day of the
week. The day begins at 00.00 and ends at 24.00. The
machine will be in unoccupied mode unless a scheduled
time period is in effect. If an occupied period is to extend
past midnight, it must be programmed in the following
manner: Occupied period must end at 24:00 hours
(midnight); a new occupied period must be programmed
to begin at
0O:OO
hours.
The time schedule can be overridden to keep the unit
in the occupied mode for one, 2, 3 or 4 hours on a one-
time basis.
Ilemand Limit Set
Poiot5
Step I Capacity Reduction:
0% to
100%
Step 2 Capacity Reduction:
0% to
100%
Set points a
re
grouped in subfunctions as follows:
Displays chilled water set points.
a.
The first
set point.
value shown is the occupied chilled water
b. The next value to
be
schedule function h
displayed depends on
.as
been programmed. (See
how the
below.)
If dual set point
-
has been selected, the next set point
after
L-J
+
has been pressed will be the unoccupied
chilled water set point; this will be followed by the
modified chilled water set point.
I1