Daikin WMC Installation, Operation And Maintenance Manual page 35

Figure 37: (III) VALVE STAGE -
Valve Opening vs. Temperature
100
80
60
40
20
0
65 70
Temperature (°F)
4 Fan Stages
As shown in Figure 37, the default minimum and maximum
valve opening positions are 20% and 100%, respectively.
These minimum and maximum positions are adjustable
anywhere between 0% and 100%. Additional fans stage on
when the valve opening position reaches the maximum value
that was set.
(IV) VFD STAGE: In this mode, a VFD controls the first fan.
Up to three more fans are staged on and off and there is
no bypass valve. See
Figure 38: TOWER Setpoint - SP2 - (IV) VFD STAGE
Cooling Tower
Fan Staging
(Up to 4 fans)
Tower
Control
Panel
0-10 VDC
w/ Fan
Signal
VFD
MicroTech II
®
Controller
Condenser
Figure 39: (IV) VFD STAGE - VFD Speed vs. Temperature
100
80
60
40
20
0
65 70
Temperature (°F)
4 Fan Stages
www.DaikinApplied.com
75 80 85
1 Fan Stage
Figure 38 and Figure 39.
75 80 85
1 Fan Stage
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.
(V) VALVE SP / VFD STAGE: This control strategy is tower
fan control with a VFD and bypass valve control. See
Figure 40 and
Figure 40: TOWER Setpoint - SP2 - (V) VALVE SP /
Cooling Tower
90
Fan Staging
(Up to 4 fans)
0-10 VDC
Signal
MicroTech II
®
Controller
Condenser
Figure 41: (V) VALVE SP / VFD STAGE
Percent vs. Temperature
100
80
60
40
20
0
60 65
% VFD Speed (4 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,
41 shows that the default temperature at which the valve opens
completely is 65°F. This temperature is the Valve SP and is
adjustable.
90
33 IOM 1210-1 • MAGNITUDE
39, the default minimum and maximum
Figure 41.
VFD STAGE
Tower
Control
Panel
w/ Fan
VFD
Bypass Line
0-10 VDC Signal
70 75 80
Temperature (°F)
% VFD Speed (1 Fan Stage)
41, the default minimum and maximum
MODEL WMC CHILLERS
®
o
peraTIon
Bypass
Valve
85 90
Figure