Daikin DPS Installation And Maintenance Manual page 74

OAT Temperature Sensor Problem - (OAT
Sensor: Problem)
If the outside air temperature sensor (OAT) is present, a valid
OAT value is not provided via the network and the local OAT
sensor is either shorted or open circuited for longer than the
Sensor Alarm Delay (default is 30 seconds), the Outside
Air Sensor problem occurs . When the OAT Sensor problem
occurs, the unit continues to operate with the following
modifications:
• Compressor heating and cooling operations are locked out .
• Cooling Reset and Heating Reset revert to none if they
are set to OAT
• Economizer is locked out due to high OAT
When the alarm condition is no longer present, the OAT Sensor
problem automatically clears .
Freeze Problem - (Freeze: Problem)
When a unit is equipped with a hot water coil, the Freeze
problem occurs when the optional freezestat contacts open
as a result of detecting an abnormally low water or steam coil
temperature while the fans are off .
When the Freeze problem occurs, the controller opens the
heating valve, and sets a 10-minute timer . When the 10-minute
timer expires, the controller checks the freezestat input again .
If the freezestat contacts are closed the valve closes . If the
freezestat contacts are still open the valve remains open,
and the 10-minute timer resets . This continues while the
unit remains off . Whenever the freezestat closes the Freeze
problem automatically clears . This feature protects the coil
and allows the system to start normally when an occupied
command is received .
Indoor Refrigerant Temperature Sensor
Problem (Heat Pump only) – (IRT Sensor:
Problem)
This alarm occurs when the IRT sensor input is outside the range
of -4°F to 150°F continuously for the Sensor Alarm Delay (default
30 seconds) . When this alarm is active compressor heating
operation is disabled if HtgEVIMethod is set to "Sbc" . Otherwise
not action is taken . The alarm must be manually cleared once
corrective action is taken .
Outdoor Refrigerant Temperature Sensor
Problem (Heat Pump only) – (ORT Sensor:
Problem)
This alarm occurs when the ORT sensor input is outside the
range of -4 to 150°F continuously for the Sensor Alarm Delay
(default 30 seconds) .
When this alarm is active compressor cooling operation is
disabled if ClgEVOMethod is set to "Sbc" . Otherwise not action is
taken .
The alarm must be manually cleared once corrective action is
taken .
OM 1141-3 • MICROTECH UNIT CONTROLLER
Fixed Speed Compressor Discharge
Line Refrigerant Temperature Sensor
Problem – (DRT3 Sensor: Problem)
This alarm occurs when the DRT3 sensor input is shorted or open
circuited for the Sensor Alarm Delay (default 30 seconds) . It can
also occur when the fixed speed compressor is off and the input is
above 329°F or the compressor has been off for 20 minutes and
the input is below -4°F .
When this alarm is active the fixed speed compressor is disabled.
The alarm must be manually cleared once corrective action is
taken .
Inverter Compressor Discharge Line
Refrigerant Temperature Sensor Problem
– (DRT1 Sensor: Problem)
This alarm occurs when the DRT1 sensor input is shorted or open
circuited for the Sensor Alarm Delay (default 30 seconds) . It can
also occur when the inverter compressor is off and the input is
above 329°F or the compressor has been off for 20 minutes and
the input is below -4°F .
When this alarm is active compressor cooling and heating
operation are disabled .
The alarm must be manually cleared once corrective action is
taken .
Inverter Compressor Problem – (INV
Comp: Problem)
This alarm occurs whenever the inverter compressor board
generates an internal fault code . Refer to the troubleshooting
section of this document for fault code details .
When this alarm is active compressor cooling and heating
operation are disabled .
The alarm must be manually cleared once corrective action is
taken .
Defrost Temperature Sensor Problem
(Heat Pump only) – (DFT Sensor:
Problem)
This alarm occurs when the DFT sensor input is shorted or open
circuited for the Sensor Alarm Delay (default 30 seconds) . It can
also occur if the input is outside the range of -47°F to 194°F .
When this alarm is active compressor cooling and heating
operation are disabled .
The alarm must be manually cleared once corrective action is
taken .
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