Daikin MicroTech III Operation Manuals page 85

High Return Air Temperature - (Hi Return Tmp: Fault)
If the return air temperature is greater than the Return Air
Temperature Limit (Default = 120°F) and the supply fan has
been on for longer than the temperature alarm delay (Default
= 30 seconds), the High Return Air Temperature fault occurs .
When the High Return Air Temperature fault occurs, the unit
is shut down . It remains shut down until the High Return Air
Temperature fault is manually cleared through the unit keypad
or via a network signal .
Duct High Limit Fault - (Duct Hi Limit: Fault)
If the unit is variable air volume, the contacts of the duct high
pressure limit control (DHL) open, and the unit state is not Off
or Startup, the Duct High Limit fault occurs . When the Duct
High Limit fault occurs, the unit is shut down . The unit remains
shut down until the Duct High Limit fault is manually cleared
through the unit keypad or via a network signal .
Discharge Air Sensor Fault -(Disch Tmp: Fault)
If the discharge air temperature sensor (DAT) is open or
short circuited for longer than the Sensor Alarm Delay
(Default= 30 seconds), the Discharge Air Sensor fault occurs .
When the Discharge Air Sensor fault occurs, the unit is shut
down . It remains shut down until the Discharge Air Sensor
fault is manually cleared through the unit keypad or via a
networksignal .
Control Temperature Fault - (Control Temp: Fault)
If the temperature sensor (ZNT1, RAT, OAT, MAT) selected
as the control temperature source is not reliable for longer
than the Sensor Alarm Delay (Default= 30 seconds), a Control
Temperature Fault occurs . When the Control Temperature
Fault occurs, the unit is shut down . It remains shut down until
the Control Temperature Fault is manually cleared through the
unit keypad or via a network signal .
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Emergency Stop Fault - (Emerg Stop: Fault)
An Emergency Stop Fault will occur if either of the following
conditions is true:
• Emergency Stop Input in the Alarm (Open) condition
• The Net Emrg Ovrd input is set to Off via a network signal
or the keypad/display
Freeze Fault - (Freeze: Fault)
When a unit is equipped with a waterside economizer, chilled
water, hot water, or steam coil, the Freeze Fault occurs when
the optional freezestat contacts open as a result of detecting
an abnormally low water or steam coil temperature while the
fans are running .
When the Freeze fault occurs, the controller shuts down
the fans, opens the chilled water, economizer, and heating
valves and set a 10-minute timer . If the unit is equipped with
a waterside economizer, the pump output is also turned on .
When the 10-minute timer expires, the controller checks the
freezestat input again . If the freezestat contacts are closed
the pump output is de-energized and the valves close . If the
freezestat contacts are still open the pump output remains
energized, the valves remain open, and the 10-minute timer
resets . This continues until the fault is manually cleared
through the keypad or via a network signal .
NOTE: Water valves remain open and Pump output remains
on for 10 minutes after alarmconditions disappear .
85 OM 920-6 • MICROTECH UNIT CONTROLLER
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