Daikin WGZ030DA, Installation, Operation And Maintenance Manual

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www.DaikinApplied.com 63 IOM 1322 • WATER-COOLED SCROLL COMPRESSOR
Low Ambient Lockout
This feature is only available on air cooled units
(WaterCooled=Off).If the OAT drops below the low ambient
lockout set point, then all running circuits will do a normal stop.
Once the lockout has been triggered, no compressors will start
until the OAT rises to the lockout set point plus 5°F.
Unit State
The Unit will always be in one of three states. These states are
Off, Auto, and Pumpdown . Transitions between these states
are shown in the diagram on the following page.
T1: Off to Auto
Unit Enable = True AND
No Unit Alarm AND
IF Unit Mode = Cir 1 Available OR Cir 2 Available
T2: Auto to Pumpdown
Keypad Enable = Off OR
BAS Enable = Off OR
Remote Switch = Off OR
T3: Pumpdown to Off
Unit Alarm OR
Unit Switch Off OR
No Compressors Running
T4: Auto to Off
Unit Alarm OR
Unit Switch Off OR
No Compressors Running AND [Unit Mode = Ice AND Ice
Delay Active] OR
No Compressors Running AND [No Circuit Available]
Figure 36: Unit State Diagram
Evaporator Water Pump State Control (Evap State)
The state-transition diagram shown below controls operation of
the evaporator pump.
Figure 37: Evaporator Pump State Diagram
Pump Selection
The pump output used will be determined by the Evap
Pump Control set point. The setting allows the following
configurations:
#1 only – Pump 1 will always be used.
#2 only – Pump 2 will always be used.
Auto – The primary pump is the one with the least run hours,
the other is used as a backup.
#1 Primary – Pump 1 is used normally, with pump 2 as a
backup.
#2 Primary – Pump 2 is used normally, with pump 1 as a
backup.
Unit Controller Operation