Honeywell AUTOMATIC CONTROL SI Edition Engineering Manual page 360

CHILLER, BOILER, AND DISTRIBUTION SYSTEM CONTROL APPLICATIONS
TOP NUMBERS = FULL FLOW
BOTTOM NUMBERS = HALF FLOW, EACH COIL
PD = PRESSURE DROP IN kPa
12
3
108
153
36
CHILLER
9
PUMP
144
162
ZERO
REFERENCE
RETURN
12
0
3
Fig. 74. Single Pump, Pressure Bypass, Direct Return at Full and Half Flow.
SUPPLY 9.3 kPa DROP
CHILLER
27.9 kPa
DROP
*DP SETPOINT =103.5 kPa
PUMP
66 L/s
150 kPa
RETURN
9.3 kPa DROP SYSTEM STRAINER
NUMBERS IN CIRCLES = GAUGE PRESSURES (kPa)
(PUMP INLET = ZERO kPa FOR SIMPLICITY)
96
PD
150
PD
HEAT/ HEAT/
24 COOL COOL
PD
COIL COIL
6
1 2
72
144
V1
24
PD
132
48
12
B1 B2
36
PD
9
12
PD
3
SYSTEM WITH 90% FLOW THROUGH EACH COIL
HEAT/
COOL
COIL
1
DP
B1
*DIFFERENTIAL PRESSURE CONTROLLER SETPOINT = 150 kPa - 27.9 kPa - 9.3 kPa - 9.3 kPa = 103.5 kPa
Fig. 75. Single Pump, Pressure Bypass System at 90 percent Flow.
18 kPa DROP TOTAL
18
PD
4.5
HEAT/ 12 L/s
HEAT/
COOL PER
COOL
COIL
AHU COIL
COIL
3
4
V3
V2
B3
18
PD
4.5
HEAT/ 11 L/s
HEAT/
COOL COOL PER
COIL AHU COIL
COIL
3
2
V3
V1 V2
B3
B2
ENGINEERING MANUAL OF AUTOMATIC CONTROL
350
78
145.5
HEAT/
HEAT/
24
COOL
COOL
6
COIL
COIL
6
5
54
139.5
V4 V5
24
V6
132
30
7.5
B4 B5 B6
0
PD
0
30
7.5
M15286
HEAT/ HEAT/
COOL COOL
COIL COIL
4 5
V4 V5
B4 B5
PD
PD
HEAT/
COOL
COIL
6
V6
B6
M15287