84
WGS 130A to 190A
OM WGS-5
SET TOWER SPs (1)
Tower Control=None
Tower Stages= 2
When Tower Control is None, the control of condenser water temperature is not by the
MicroTech II controller and assumed to be furnished elsewhere.
Tower Stages is the number of tower fans to be staged by the controller, choices are 0, 1, or
2. "0" indicates control will be by a bypass valve or variable speed pump controlled by the
MicroTech II controller.
StageUP/DN imposes a time delay between fan stages when turning on or turning off.
SET TOWER SPs (2)
Stage 1 On =XXX
Stage 2 On =XXX
StageDiff = XX.X
SET TOWER SPs (3)
Stage Up Tmr= XX min
Stage Dn Tmr= XX min
Stage Up/Dn=XXX/XXX%
StageDiff is the number of degrees below the Stage ON that will turn off the tower fans.
For example, if Stage ON #1 is 70
F and StageDiff is 5
F, tower fan #1 will stage off when
the ECWT drops to 65
F and stage the fan on when the ECWT rises to 70
F. The same is
true for fan #2.
Stage Up timer is the number of minutes that must elapse between the condenser pump
starting (it starts with the unit) and fan #1 starting or the time between fan #1 starting and
fan #2 starting.
StageDown is the elapsed time between staging down the fan motors.
SET TOWER SPs (4)
Valve/VFD Control=
None
Valve Type=NC to twr
Valve/VFD Control settings are None, Valve Setpoint, Valve Stage, VFD Stage, or
ValveSP/VFDStage. Default is None which results in no control of the tower from the
MicroTech II controller.
Valve Setpoint, the valve will control (bypass tower) to hold the minimum temperature
as established by the Set Tower SPs in screen number 5 shown on the following page.
This mode is operational when the Valve/VFD Control setpoint is set to Valve Setpoint
OR Valve SP/VFD Stage. In this mode the valve output is varied with a proportional-
derivative (PD) algorithm (with deadband) in order to maintain the controlled parameter
(CP) at the desired value. The output is always limited between the Valve Control
Range (Min) setpoint and the Valve Control Range (Max) setpoint. A valve increment
shall be computed once every 5 seconds according to the following equation. (Error
Gain and Slope Gain are set in menu screen #8.)
Summary of Contents for WGS130AA: WGS140AW
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