Carrier 040-420 Example 9 - Using the Schedule Function, Example 9 continued next page

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

O V R D

0

No

schedule

override

in

effect

O V R D

3

3

hours

override

in

effect

O V R O

0

Override

cancelled

C L O C K

0

Schedule

function

is

inactive

CLOCK 1

Schedule

function

is

enabled

through

local

unit

clock

CLOCK

65

Schedule

function is enabled

throuah

CCN

clock

65

PERIOD

1

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

UN0

00.00

(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

MON

NO

into’ effect on

M&day,

Monday

must

be

flagged

Yes

MON

YES

Monday is now fla ged for

period 1 to be in eaect

For this example, period 1

is to be in effect on Monday

TUE

YES

only All other days must be

checked to be sure that thev

are flagged no. If any day ii

flagged yes, change to no

TUE NO

Tuesday

is

now

flagged

no for period 1

PERIOD 2

Define

schedule

period

2

occ

00

00

Start

of

occupied time

occ 7 00

C$uo$e;;me will start

Start

of

unoccupied

time

UN0

00.00

(end of period) For this

example, period 2 should

end at 18:00 (6:00 p m )

UN0

18 00

Period 2 ends at 18:OO

(6:00 p

m

)

Monday is now flagged no

MON

NO

for period 2 To put period 2

into

effect

on

Monday,

Monday must be flagged yes

MON YES

Monday is now flagged for

period 2 to be in effect

Tuesay is now flagged no

for period 2 To put period 2

TUE

NO

into

effect

on

Tuesday,

Tuesday

must

be

flagged

yes

TUE

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

WED YES

All other days must be

checked to be sure that

they are flagged no. If

a day is flagged yes,

change

to

no

W E D N O

Wednesday

is

now

flagged

no

for

period

2

CCN - Carrier Comfort Network

Example 9 continued next page.

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