39
IOM 1297
WWW.DAIKINAPPLIED.COM
OPERATION
CAUTION
Changing Low Evaportator Pressure setpoint below psi minimum requires
glycol to be added to the system otherwise there is a risk of freezing the
evaporator.
Figure 43: Settings View - Commission
Table 13: Commission Setpoint Settings
Description
Default
Range
PW
Comments
Compressor
IGV
Maximum
Position
98%
90-110%
T
98% indicates vanes
are straight
NOTICE
If both compressors have the same sequence number, they
will automatically balance starts and run-hours. User cannot
manually stage compressors as this is an internal process.
Figure 44: Settings View - Interface
Table 14: Unit Interface Settings
Description
Default
Range
PW
Comments
BAS
Network
Protocol
NONE
NONE,
MODBUS,
LON-
WORKS,
BACnet IP, ,
BACnet MS/
TP
O
NONE: No BAS
network
MODBUS: RTU -
RS485
LONWORKS:
LONtalk - FTT-
10A
BACnet IP: IP -
Ethernet
BACnet MS/TP:
RS485
NOTICE
It is likely that the chiller will contain the factory settings for date
and time; therefore, it is important to verify or change these
settings when the chiller is first used on the jobsite. Failure to do
so will result in incorrectly labeled History files.
NOTICE
The version numbers shown towards the bottom left of the screen
are the controllers’ software identification. These numbers may
be required by Daikin Applied to answer questions about unit
operation or to assist in possible future upgrades of software.
Compressor Capacity Control
Compressor capacity is determined by the status of the leaving
chilled water temperature (LWT), which is a direct indicator
of whether the chiller is producing enough cooling to satisfy
the cooling load. The LWT is compared to the active chilled
water setpoint, and compressor loading or unloading ensues,
considering any capacity overrides that may be in effect.
Capacity Overrides
The conditions described in the following sub-paragraphs
override normal capacity control. Of the following limits, the one
creating the lowest capacity limit is in effect.
Low Evaporator Pressure
If the evaporator pressure approaches within 2 psi above the
Low Evaporator Pressure setpoint, the unit will inhibit capacity
increases. If the evaporator pressure approaches within 1 psi
above the Low Evaporator Pressure setpoint, the unit may unload
if chiller conditions necessitate it.
High Motor Temperature
If the highest motor stator temperature is above the limit, the unit
will adjust capacity to keep the temperature within the limits.
