McQuay WSC Operating Manual page 29

Cooling Tower Bypass VALVE Settings
Figure 17, Tower Bypass VALVE Setpoint Screen
Table 15, Tower Bypass VALVE Setpoints (See page 31 for complete explanation.)
Description
Slope Gain
Error Gain
Valve Control Range(Max)
Valve Control Range (Min)
Temp - Maximum Position
Maximum Start Position
Temp - Minimum Position
Minimum Start Position
Stage Down @
Stage Up @
Valve Deadband (Lift)
Valve Deadband (Temp)
Valve Target (Lift)
Valve Setpoint (Temp)
Valve Type
OM Centrif Micro ΙΙ-5
No. Default Range
15 25 10 to 99
14 25 10 to 99
13 100% 0 to 100%
12 10% 0 to 100%
11
90 °F 0 to 100 °F
10 100% 0 to 100%
9
60 °F 0 to 100 °F
8 10% 0 to 100%
7 20% 0 to 100%
6 80% 0 to 100%
1.0 to 20.0
5 4.0 psi
psi
1.0 to 10.0
4 2.0 °F
°F
10 to 130
3 30 psi
psi
40 to 120
2 65 °F
°F
NC (To
1 NC, NO
Tower)
Pass-
Comments
word
M Control gain for temperature (or lift) slope
M Control gain for temperature (or lift) error
Maximum valve position, overrides all other
M
settings
M Minimum valve position, overrides all other settings
Condenser EWT at which valve should be open to
M
tower
Initial valve position when condenser EWT is at or
M
above Setpoint # 9
Condenser EWT at which initial valve position is
M
set to Setpoint # 6
Initial position of valve when condenser EWT is at
M
or below Setpoint # 7
Valve position below which the fans can stage
down (Tower Setpoint #2 = Valve Stage Down
M
VFD speed below which the next fan speed can
turn off (Tower Setpoint # 2 = valve/VFD ????
Valve position above which the fans can stage up
(Tower Setpoint #2 = Valve Stage Down
M
VFD speed above which the next fan speed can
turn on (Tower Setpoint # 2 = valve/VFD ????
M Control deadband, Tower Setpoint #1=Lift
M Control deadband, Tower Setpoint #1=Temp
Target for lift pressure (Tower Setpoint #1= Lift),
M
Works with Setpoint # 5
Target for condenser EWT (Tower Setpoint #1=
M
Temp), Works with Setpoint # 4
M Normally closed or normal open to tower
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