Dual Cooling Tower Variable Speed Fan Control - Honeywell AUTOMATIC CONTROL SI Edition Engineering Manual

CHILLER, BOILER, AND DISTRIBUTION SYSTEM CONTROL APPLICATIONS

DUAL COOLING TOWER VARIABLE SPEED FAN CONTROL

Functional Description
5
V1T
100
4
0
COOLING
V1S
TOWER 1
12
25.5
10
25.5
1
2
Item No. Function
1,2 Dual dynamic pump symbols indicate pump
operational status.
3 OA Conditions dictate freeze-protection and
optimized setpoint control strategies.
4-7 Valves provide tower isolation, modulating
low limit condenser water control when OA
temperature is above freezing, and two
position low limit operation when OA
temperature is below freezing.
8,9 Indicates tower fans speed (percent).
7
9
8
33
33
COOLING
TOWER 2
25.5
13
11
TOWER FAN CONDENSER WATER
TEMPERATURE SETPOINT EQUALS OA WET BULB
TEMPERATURE PLUS
7.0
DEGREES
71
78
MINIMUM
CURRENT
32.5
14
ON
STATUS
OFF
29.5
15
Fig. 31. Dual Cooling Tower Variable Speed Fan Control Graphic
V2T
100
6
23
0
V2S
85
MAXIMUM
18
7
CHILLER 1
78
100
PERCENT LOAD
16
MAX
CURRENT
00
100
17
13
CHILLER 2
10 Input for common condenser water
temperature control.
11 Optimum condenser water temperature
calculation based upon OA WB.
12-22 Operator information.
23 Isolates towers if required.
24 Icon, for dynamic control and setpoint
display.
25 Icon to select tower low load control dynamic
sequence display.
ENGINEERING MANUAL OF AUTOMATIC CONTROL
320
TOWER ISOLATION
SELECTOR
0
0 = NO TOWERS ISOLATED
1 = TOWER 1 ISOLATED
2 = TOWER 2 ISOLATED
SETPOINTS/
SEQUENCES
24
OUTSIDE AIR
TEMPERATURE
30.5
3 21.5
DRY WET
BULB
BULB
20
7.1
21
AUTO
CHILLER
13
CONTROL
22
25
19
AUTO
M15264