IOM 1322 • WATER-COOLED SCROLL COMPRESSOR 90 www.DaikinApplied.com
Compressor Motor Protection Module
The 20, 26, and 30 HP compressors are equipped with an
module that provides protection against:
• High motor temperature
• High scroll temperature
• Phase missing
• Phase reversal
• Low control circuit voltage
The module also has a LED display in the upper righthand
corner that gives information on compressor operation.
The module is accessible by removing the compressor motor
cover. Additional information can be downloaded by authorized
service technicians using special equipment.
NOTE: If a compressor with CoreSense Communications
fails in the eld, the CoreSense module should
remain with the failed compressor so the manufacturer
can download the CoreSense data to assist with
determining the root cause of compressor failure.
DANGER
LOCKOUT/TAGOUT all power sources prior to starting, pressurizing,
de-pressuring, or powering down the Chiller. Failure to follow this warning
exactly can result in serious injury or death. Be sure to read and understand
the installation, operation, and service instructions within this manual.
WARNING
Disconnect the compressor three-phase power before removing the
terminal box cover. Removal of the terminal box cover will expose the three-
phase power connections. Contact with them can cause serious injury or
death. Servicing should be done by technicians familiar with this equipment.
• Code 1 – Loss of Communication: The module will ash
the green Warning LED one timeindicating the module
has not communicated with the master controller for
longer than 5 minutes. Once communication is reinitiated,
the Warning will be cleared.
• Code 2 – Reserved For Future Use
• Code 3 – Short Cycling: The module will ash the green
Warning LED three times indicating thecompressor has
short cycled more than 48 times in 24 hours. A short cycle
is dened as compressor runtime of less than 1 minute.
The Warning will be activated when the “Short Cycling”
dipswitch (#10) is “o” or in the “down” position. When
fewer than 48 short cycles are accumulated in 24 hours
the Warning code will be cleared.
• Code 4 – Open/Shorted Scroll Thermistor. The module
will ash the green Warning LED four times indicating
the scroll NTC thermistor has a resistance value that
indicates an open/shorted thermistor (see Table 2). The
Warning will be cleared when the resistance value is in
the normal range.
Code 1 – Motor High Temperature: The module will ash
the red Alert LED one time indicating the motor PTC circuit
has exceeded 4.5K Ohms. A code 1 Alert will open the
M2-M1 contacts. The Alert will reset after 30 minutes and
the M2-M1 contacts will close if the resistance of the motor
PTC circuit is below 2.75K Ohms. Five consecutive Code
1 Alerts will lockout the compressor. Once the module has
locked out the compressor, a power cycle or Modbus reset
command will be required for the lockout to be cleared.
Code 2 – Open/Shorted Motor Thermistor: The module will
ash the red Alert LED two times indicating the motor PTC
thermistor circuit has a resistance value that indicates an
open/shorted thermistor chain (see Table 2). A Code 2 Alert
will open the M2-M1 contacts. The Alert will reset after 30
minutes and the M2-M1 contacts will close if the resistance
of the motor PTC circuit is back in the normal range. The
module will lockout the compressor if the trip condition exists
for longer than 6 hours. Once the module has locked out the
compressor, a power cycle or Modbus reset command will
be required to clear the lockout.
Code 3 – Short Cycling: The module will ash the red
Alert LED three times indicating the compressor is locked
out due to short cycling. A Code 3 Alert will open the
M2-M1 contacts. Code 3 will be enabled when the “Short
Cycling” dipswitch (#10) is “on” or in the “up” position and
the compressor has exceeded the number of short cycles
congured by the user in a 24 hour period. Once the module
has locked out the compressor, a power cycle or Modbus
reset command will be required to clear the lockout.
Code 4 – Scroll High Temperature: The module will ash the
red Alert LED four times indicating the scroll NTC circuit is
less than 2.4K Ohms. A Code 4 Alert will open the M2-M1
contacts. The Alert will reset after 30 minutes and the M2-
M1 contacts will close if the resistance of the scroll NTC
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