IOM 1322 • WATER-COOLED SCROLL COMPRESSOR 82 www.DaikinApplied.com
The last action to take place is the shuto of all compressors
running when the LowEvPrStop setting is reached (default is
58 psi). Reducing these time intervals will increase detrimental
compressor cycling. It is recommended that these settings not
be changed.
SET ALARM LMTS (2)
High Cond Pressure
Unload is a limit alarm that unloads the unit at 370 psi in an
attempt to prevent total shutdown from the HighCondPr at 380
psi. The stage down is set at 370 psi. It is recommended that
these settings not be changed.
Stop (the unit high-discharge-pressure shutdown) is a stop
alarm that shuts o the unit when the discharge pressure
reaches the setting. The default setting is 380 psi.
LowEvPrDelay is a time delay on the low pressure trip that
reduces nuisance low-pressure trips. The default setting is 30
seconds.
SET ALARM LMTS (3)
Evap Freeze (the unit freeze protection shutdown) is actually
a stop alarm and shuts o the unit when the LWT reaches
36°F. It is cleared by going to the CLEAR ALARM menu in the
ACTIVE ALARM hierarchy.
EvapFlowProof is the ow switch interlock. Closing the ow
switch and therefore proving the existence of chilled water ow
resets this trip. It is recommended that these settings not be
changed.
LowAmbientLock applies to units with air-cooled condensers
and prevents unit operation below the setting. The available
range is -2°F to 60°F with a default of 35°F.
SET ALARM LIMITS (5)
TGZ in Heat Mode
SET ALARM LIMITS (6)
Stg2 Stg3 Stg4
XXX XXX XXX
Stg2 Stg3 Stg4
XXX XXX XXX
The SET FANS SP screens 2 through 5 establish the
temperature that will stage the condenser fans on and o.
These screens apply only to units set up for use with air-cooled
condensers (WaterCooled=No). On such units, the settings do
not have to be entered if the unit controller is not used to stage
condenser fans for head pressure control. If the MicroTech
II unit controller is not used to control the fans, some other
method must be used.
Cond Sat Temp Target
X X X
Set Cooling Tower Control
The MicroTech II controller is capable of controlling cooling
tower water temperature on chillers using water-cooled
condensers. Output wiring connection points are shown on the
eld wiring diagrams.
[Water Cooled = Y] - Condenser Pump on with rst
Compressor on. Tower fan control is active when the
Tower Control setpoint is set to Temperature and the
condenser pump is in the RUN state. Staging is based on
Entering Condenser Water Temperature (ECWT). Operation
depends on the following.
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