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The schedule function can be programmed for inactive,
single set point, or dual set point operation.
When schedule is configured for inactive, chilled water
pump relay remains energized continuously but is not used
since chiller is usually controlled by remote chilled water
pump interlock contacts.
When unit is configured for single set point operation,
chilled water pump relay is energized whenever chiller is in
occupied mode regardless of whether chiller is running. When
chiller is in unoccupied mode, chilled water pump relay is
not energized.
When unit is configured for dual set point, chilled water
pump relay is energized continuously, in both occupied and
unoccupied modes. Occupied mode places occupied chilled
water set point into effect; unoccupied mode places unoc-
cupied chilled water set point into effect.
The schedule consists of from one to 8 occupied time pe-
riods, 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
.OO
and ends at 24.00. The machine is in
unoccupied mode unless a scheduled time period is in ef-
fect, If an occupied period is to extend past midnight, it
must be programmed in the following manner: occupied pe-
riod must end at
24:OO
hours (midnight); a new occupied
period must be programmed to begin at
0O:OO
hours.
NOTE: This is true only if the occupied period starts at
0O:OO
(midnight). If the occupied period starts at a time
other than midnight, then the occupied period must end at
0O:OO
hours (midnight) and new occupied period must be
programmed to start at
0O:OO
in order for the chiller to stay
in the occupied mode past midnight.
The time schedule can be overridden to keep unit in oc-
cupied mode for one, 2, 3 or 4 hours on a one-time basis.
See Example 9.
All subfunctions of schedule function are password pro-
tected except the override subfunction,
17
b[
.
Pass-
word entry into subfunctions
f;l
b[
through
m
m
b[,
is done through service function. See page 44, logging on/
logging off.
Figure 9 shows a schedule for an office building with the
chiller operating on a single set point schedule. The sched-
ule is based on building occupancy with a 3-hour off-peak
cool-down period from midnight to 3 a.m. following the
weekend shutdown. To learn how this sample schedule would
be programmed, see Example 9.
NOTE: This schedule was designed to illustrate the pro-
gramming of the schedule function and is not intended as a
recommended schedule for chiller operation.
Example 9
-
Using the Schedule Function
DISPLAY
OVRD 0
OVRD 3
OVRO 0
CLOCK 0
CLOCK 1
CLOCK 65
PERIOD 1
UN0
00.00
MON NO
MON YES
TUE YES
TUE NO
PERIOD 2
occ 00 00
occ 7 00
UN0
00.00
UN0
18 00
MON NO
MON YES
TUE NO
TUE YES
WED YES
WED NO
No schedule override
in effect
3 hours override in effect
Override cancelled
Schedule function is inactive
Schedule function is enabled
through local unit clock
Schedule function is enabled
throuah CCN clock 65
Define schedule period 1
Start of occupied time
For this example, first
period should stat-t here
/;tntnnr$ht)
so no entry
Start of unoccupied time
(end of period) For this
&xampl&
period 1 should
end at 3:00 a m.
Period 1 ends at 3:00 a m
Monday is now flagged no
for oeriod 1 To out
oeriod
I
into’ effect on
M&day,
Monday must be flagged
Yes
Monday is now fla
aperiod
1
to be in e
ged for
ect
For this example, period
1
is to be in effect on Monday
only All other days must
be
checked to be sure that thev
are flagged no. If any day
ii
flagged yes, change to no
Tuesday is now flagged
no for period
1
Define schedule period 2
Start of occupied time
C$uo$e;;me will start
Start of unoccupied time
(end of period) For this
example, period 2 should
end at 18:00 (6:00 p m )
Period 2 ends at 18:OO
(6:00 p m )
Monday is now flagged no
for period 2 To put period 2
into effect on Monday,
Monday must be flagged yes
Monday is now flagged for
period 2 to be in effect
Tuesay is now flagged no
for period 2 To put period 2
into effect on Tuesday,
Tuesday must be flagged
yes
Tuesday is now flagged for
period 2 to be in effect
For this example, period 2
is to be in effect only on
Monday and Tuesday
All other days must be
checked to be sure that
they are flagged no. If
a day is flagged yes,
change to no
Wednesday is now flagged
no for period 2
CCN
-
Carrier Comfort Network
Example 9 continued next page.
46