Multiple Centrifugal Chiller Sequencing - Honeywell AUTOMATIC CONTROL Engineering Manual

Multiple Centrifugal Chiller Sequencing

FUNCTIONAL DESCRIPTION
T T
SP4
45.0
45.0
C C
H H
O
I I
O
F
L
L
N
F
L
L
E
E
R
R
4
3
P
P
P4
P3
Y
G
Item No. Function
1,2 Secondary pump speeds.
3 Icon for selection of secondary control details.
4 Secondary pump leaving water temperature
(operator information).
5 Four chiller pump status indicators (green = on,
yellow = off, red = alarm) (typical).
6 Four Icons for selection of chiller detail graphic.
7 Four chiller status indicators (typical), operator
information.
8 BMCS commandable AUTO-OFF functions for
each chiller and ON-OFF-AUTO functions for
each chiller pump.
9 Decoupler temperature—indicates direction of flow.
CHILLER, BOILER, AND DISTRIBUTION SYSTEM CONTROL APPLICATIONS
FAN AND TOWER ISOLATION
VALVE CONTROL (TYPICAL)
CT
4
85.0
Fig. 18. Digital control of Sequenced Cooling Towers.
T
T
SP3
SP2 SP1
45.0
45.0
18
SETPOINT
20
C
C
H
H
O
I
I
O
F
L
L
N
F
L
L
SEQUENCING
E
E
7
R R 21
6
2
1
P
P
P2 P1
5
Y
G
13
T
RP
53.8
Fig. 19. Control Graphic for Multiple Similar Chillers.
COMMUNICATION WITH
CONDENSER PUMP/ CHILLER
CONTROLLERS
COOLING TOWER
STAGING & LOADING
CONTROLLER
CT
CT
CT
1
3 2
M10501
T
SP
45.0
14
16 45.0
19
45.0
T
SS
SETPOINT
CONTROL
CHILLER
45.0
T
D PLANT CONTROL
CHILLERS
9
DECOUPLER
1
AUTO
LINE
2
AUTO
3
AUTO
PC
200
12
4
AUTO
GPM
10
11
FS
FP
GPM
GPM
1600 1400
10 Primary flow—indicates primary loop loading.
11 Secondary flow—indicates secondary loop loading.
12 Decoupler flow the difference between primary
and secondary flows.
13-16 Temperatures for calculating secondary flow.
17 Status of optional AUTO-MANUAL toggle switch.
18 Four chiller CHWS temperature indicators.
19 Operator information (from secondary system).
20 Icon for selection of chilled water setpoint details
display.
21 Icon for selection of chiller sequencing display
(Fig. 20).
313 ENGINEERING MANUAL OF AUTOMATIC CONTROL
1
% SPEED
74
3
SECONDARY
SYSTEM
P
S2
% SPEED
0
45.8
2
T
4
SS
8
PUMPS
AUTO
AUTO
AUTO
SYSTEM
AUTO-MANUAL
AUTO
SWITCH STATUS
AUTO
55.0
T
RS
15
17
M10502