Daikin WGZ030DW, Installation, Operation And Maintenance Manual

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IOM 1322-1 • WATER-COOLED SCROLL COMPRESSOR 54 www.DaikinApplied.com
Unit Controller
set point is set to Valve Stage. In this mode the valve output
is controlled as for Valve Set point mode (above), except that
the active set point for the controlled parameter is selected
according to the following table.
# Of Fans ON Active Set point
0 Valve Set point
1 Stage #1 ON
2 Stage #2 ON
3 Stage #3 ON
4 Stage #4 ON
VFD Stage, ValveSP/VFDStage, When the Valve/VFD Control
set point is set to None, Valve Set point, OR Valve Stage, this
output is set to 0. Otherwise, it will be controlled in a manner
identical to Valve Stage Mode (above) except that (1) it shall be
kept at zero until the first fan stage is ON, and (2) the following
set points do not apply.
Valve Control Range (Min)
Valve Control Range (Max)
Valve Type
Valve Type settings are NC (normally closed to tower) or NO
(normally open).
These settings establish the operation of a tower bypass valve
(must be a 3-way valve).
Initial Valve Position
When the condenser pump is not in the RUN state, the valve
output shall be set as a function of entering condenser water
temperature (ECWT) per the following graph.
Figure 26: Initial Valve Position
Operation After Start
When the condenser pump is in the RUN state, the valve
output shall be controlled in one of two modes as specified
by the Valve/VFD Control set point. The controlled parameter
shall be the condenser entering water temperature. When the
desired output signal varies from 0 to 100%, the output voltage
shall vary as shown below.
0 to 10 VDC (Valve Type = NC)
10 to 0 VDC (Valve Type = NO)
Water-cooled = Y
SET TOWER SPs (5)
Valve SP = XXX °F
Valve DB = XX .X °F
Valve SP is the minimum tower water temperature acceptable,
default is 65°F.
Valve DB is the dead-band in degrees, default is 2.0°F.
Water-cooled = Y
SET TOWER SPs (6)
ValveStartPosition
Min = XXX% @XXX°F
Max = XXX% @XXX°F
The ValveStartposition is the position of the valve when the unit
starts. Default for minimum start position is 0%, and 100% for
maximum position.
Water-cooled = Y
SET TOWER SPs (7)
Valve Control Range
Min = XXX%
Max = XXX%
Defaults are 10% minimum and 90% maximum.
Water-cooled = Y
SET TOWER SPs (8)
PD Control Loop
Error Gain = XX
Slope Gain = XX
Defaults are 25 for both error and slope.
Alarms
When an alarm occurs, the alarm type, limit value (if any), date,
and time are stored in the active alarm buffer corresponding
to that alarm (viewed on the Alarm Active screens) and also
in the alarm history buffer (viewed on the Alarm Log screens).
The active alarm buffers hold a record of the last occurrence of
each alarm and whether or not it has been cleared. The alarm
can be cleared by pressing the Edit key. A separate buffer is
available for each alarm (High Cond Pressure, Evaporator
Freeze Protect, etc.). The alarm history buffer holds a
chronological account of the last 25 alarms of any type.