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Figure 63: Strategy (IV) - NONE
Cooling Tower
Fan Staging
(Up to 3 fans)
Tower
Control
Panel
MicroTech
®
Controller
Condenser
Figure 64: Strategy (IV) NONE - Temp vs. Fan Stages
95
90
85
80
75
70
65
0
1
Strategy (V) VALVE SP /VFD STAGE:
This control strategy is tower fan control with a VFD and
bypass valve control. See
Figure 65
To set up in HMI, do the following:
A. The TOWER Setpoint setting for Cooling Tower Control
strategy should be NONE. Tower Valve/VFD should be
changed to VALVE SP/VFD STAGE.
B. Use all of the same setpoint settings as outlined in
Strategy (II) - section B for Temp or section C for Lift. .
Figure 65: Strategy (V) - VALVE SP/VFD STAGE
Cooling Tower
Fan Staging
(Up to 3 fans)
Tower
Control
Panel
0-10 VDC
w/ Fan
Signal
VFD
MicroTech
®
Controller
Condenser
IOM 1274-3 • CENTRIFUGAL WATER CHILLERS
2
3
4
Fan Stages
and
Figure
66.
Bypass
Bypass Line
0-10 VDC Signal
Figure 66: Strategy (V) VALVE SP / VFD STAGE - Percent
vs. Temperature
100
80
60
40
20
0
60
65
% VFD Speed (3 Fan Stages)
% Valve Opening
As shown in
Figure
VFD speeds are 20% and 100%, respectively. These minimum
and maximum values are adjustable anywhere between 0%
and 100%. Additional fans stage on when the VFD speed
reaches the maximum value that was set. In addition,
66
shows that the default temperature at which the valve opens
completely is 65°F. This temperature is the Valve SP (also
called Valve Target) and is adjustable.
5
BAS Alternate
In control strategies (I) through (V), the chiller MicroTech®
is directly controlling the cooling tower fan staging, variable
frequency drives, and bypass valves. As an alternative, a BAS
can control these components based on a signal from the
MicroTech
controller. See
®
Figure 67: BAS Alternate
MicroTech
®
Controller
Condenser
Valve
54
70
75
80
Temperature (°F)
% VFD Speed (1 Fan Stage)
66, the default minimum and maximum
Figure
67.
Tower
Control
Panel
w/ Fan
VFD
Bypass Line
0-10 VDC Signal
www.DaikinApplied.com
Operation
85
90
Figure
BAS
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