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www.DaikinApplied.com 37 IOM 1266-2 • MAGNITUDE
®
MODEL WME CHILLERS
Table 16: Tower Setpoint Settings
Description Default Range PW Comments
Valve Control Slope Gain 25 10 to 99 O Control gain for temperature (or lift) slope
Valve Control Error Gain 25 10 to 99 O Control gain for temperature (or lift) error
Valve Control Range (Max) 90% 0 to 100% O Maximum valve position, overrides all other settings
Valve Control Range (Min) 10% 0 to 100% O Minimum valve position, overrides all other settings
Temp–Max Start Position 90°F 0 to 100°F O Condenser EWT at which initial valve position is set to max start position
Maximum Start Position 100% 0 to 100% O Initial valve position when condenser EWT is at or above Temp-Max Start Position
Temp – Min Start Position 60°F 0 to 100°F O Condenser EWT at which initial valve position is set to minimum start position
Minimum Start Position 0% 0 to 100% O
Minimum position of valve when condenser EWT is at or below Temp-Min Start
Position
Stage Down @ 20% 0 to 100% O
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)
Stage Up @ 80% 0 to 100% O
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)
VFD Minimum Speed 70% 0-100% Minimum VFD speed for tower fan
Valve Deadband (Lift) 4.0 psi 1.0 to 20.0 psi O Sets control deadband, Cooling Tower Control = Lift
Valve Deadband (Temp) 2.0°F 1.0 to 10.0°F O Sets control deadband, Cooling Tower Control = Temp
Valve Target (Lift) 30 psi 10 to 130 psi O
Target for lift pressure (Cooling Tower Control = Lift), Works with Fan Stage Down
Time
Valve Target (Temp) 65°F 40 to 120°F O
Target for condenser EWT (Cooling Tower Control = Temp),
Works with Fan Stage Up Time
Tower Valve Type NC (To Tower) NC, NO O Normally closed or normally open to tower
Stage #2 On (Lift) 45 psi 10 to 130 psi O Lift pressure for fan stage #2 on
Stage #1 On (Lift) 35 psi 10 to 130 psi O Lift pressure for fan stage #1 on
Stage #2 On (Temp) 75°F 40 to 120°F O Temperature for fan stage #2 on
Stage #1 On (Temp) 70°F 40 to 120°F O Temperature for fan stage #1 on
Stage Differential (Lift) 6.0 psi 1.0 to 20.0 psi O Fan staging deadband with Cooling Tower Control = Lift
Stage Differential (Temp) 3.0°F 1.0 to 10.0°F O Fan staging deadband with Cooling Tower Control = Temp
Fan Stage Down Time 5 min 1 to 60 min O Time delay between stage up/down event and next stage down
Fan Stage Up Time 2 min 1 to 60 min O Time delay between stage up/down event and next stage up
Cooling Tower Stages 2 1 to 2 O Number of fan stages used
Tower Valve/Fan VFD
Strategy
None
None, Valve SP, Valve
Stage, VFD Stage,
Valve SP/VFD Stage
O
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
Cooling Tower Control None None, Temperature, Lift O
None: No tower fan control
Temperature: Fan and valve controlled by condenser EWT
Lift: Fan and valve controlled by lift pressure
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