IOM 1274-3 • CENTRIFUGAL WATER CHILLERS 50 www.DaikinApplied.com
Table 16: Tower Setpoint Settings
Description Default Range PW Comments
Valve Position (Bypass) 100%
Valve Control Slope Gain 1 0 to 99 T Control gain for temperature (or lift) slope
Valve Control Error Gain 20 0 to 99 T Control gain for temperature (or lift) error
Valve Control Range (Max) 100% 0 to 100% T Maximum valve position, overrides all other settings
Valve Control Range (Min) 10% 0 to 100% T Minimum valve position, overrides all other settings
Temp–Max. Start Position 90 °F 0 to 100 °F T Condenser EWT at which initial valve position is set to max start position
Maximum Start Position 100% 0 to 100% T Initial valve position when condenser EWT is at or above Temp-Max Start Position
Temp – Min. Start Position 60 °F 0 to 100 °F T Condenser EWT at which initial valve position is set to setpoint Stage Up @
Minimum Start Position 10% 0 to 100% T
Minimum position of valve when condenser EWT is at or below setpoint Stage
Down
Valve Deadband (Lift) 1.0 psi 0 to 20.0 psi T Sets control deadband, Cooling Tower Control =Lift
Valve Deadband (Temp) 1.0 °F 0 to 10.0 °F T Sets control deadband, Cooling Tower Control =Temp
Valve Target (Lift) 30 psi 1 to 100 psi T
Target for lift pressure (Cooling Tower Control = Lift), Works with Fan Stage Down
Time
Valve Target (Temp) 65 °F 40 to 120 °F T
Target for condenser EWT (Cooling Tower Control = Temp),
Works with Fan Stage Up Time
VFD Stage Down @ 20% 0 to 100% T
Valve position below which the fans can stage down
(Tower Valve/Fan VFD Strategy = Valve Stage)
VFD speed below which the fans can stage down
(Tower Valve/Fan VFD Strategy = VFD stage or valve SP/VFD stage)
VFD Stage Up @ 80% 0 to 100% T
Valve position above which the fans can stage up
(Tower Valve/Fan VFD Strategy = Valve Stage)
VFD speed above which the fans can stage up
(Tower Valve/Fan VFD Strategy = VFD or valve SP/VFD stage)
Cooling Tower Control None None, Temperature, Lift T
None: No tower control
Temperature: Fan and valve controlled by condenser EWT
Lift: Controlled by lift pressure
Tower Valve/Fan VFD
Strategy
None
None, Valve SP, Valve
Stage, VFD Stage,
Valve SP/VFD Stage
T
None: No tower valve or VFD
Valve Setpoint: Valve controls to Valve Target and Valve Deadband
Valve Stage: Valve controls between fan stages
VFD Stage: 1st fan is VFD controlled, no valve
Valve SP/VFD Stage: Both valve and VFD
Tower Valve Type NC (To Tower) NC, NO T Normally closed or normally open to tower
Cooling Tower Stages 2 1 to 4 T Number of fan stages used
Fan Stage Up Time 2 min 1 to 60 min T Time delay between stage up/down event and next stage up
Fan Stage Down Time 5 min 1 to 60 min T Time delay between stage up/down event and next stage down
65 psi 10 to 130 psi T
55 psi 10 to 130 psi T
45 psi 10 to 130 psi T
35 psi 10 to 130 psi T
6.0 psi 1.0 to 20.0 psi T Fan staging deadband with Cooling Tower Control=Lift
85 °F 40 to 120 °F T
80 °F 40 to 120 °F T
75 °F 40 to 120 °F T
70 °F 40 to 120 °F T
3.0 °F 1.0 to 10.0 °F T Fan staging deadband with Cooling Tower Control=Temp
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