Evaporator Water Temperatures Inverted; Outside Air Temperature (Oat) Lockout (A/C Units Only); Outside Air Temperature Sensor Fault Alarm (A/C Units Only) - Daikin EWAD TZ-B Operation Manual

Reset
Local HMI
Network
6.2.4

Evaporator Water Temperatures inverted

This alarm is generated any time the entering water temperature is lower than the leaving by 1°C and at least
one compressor is running since 90 seconds.
Symptom
Unit status is Off.
All circuits are stopped with a
shutdown precedure.
Bell icon is moving on controller's display.
String in the alarm list:
UnitOffEvpWTempInvrtd
String in the alarm log:
 UnitOffEvpWTempInvrtd
String in the alarm snapshot
UnitOffEvpWTempInvrtd
Reset
Local HMI
Network
Auto
6.2.5

Outside Air Temperature (OAT) Lockout (A/C units only)

This alarm prevents the unit to start if the outside air temperature is too low. Purpose is to prevent low pressure
trips at startup. The limit depends on the fan regulation that is installed on the unit. By default this value is set
to 10°C.
Symptom
Unit Status is OAT Lockout.
All circuits are stopped with a normal
shutdown procedure.
Bell icon is moving on controller's display.
String in the alarm list:
StartInhbtAmbTempLo
String in the alarm log:
 StartInhbtAmbTempLo
String in the alarm snapshot
StartInhbtAmbTempLo
Reset
Local HMI
Network
Auto
6.2.6

Outside Air Temperature sensor fault alarm (A/C units only)

This alarm is generated any time the input resistance is out of an acceptable range.
Symptom
Unit status is Off.
All circuits are stopped with a
shutdown precedure.
Bell icon is moving on controller's display.
String in the alarm list:
UnitOffAmbTempSen
String in the alarm log:
 UnitOffAmbTempSen
String in the alarm snapshot
UnitOffAmbTempSen
Reset
D-EOMZC00105-17EN
Operation Manual
60/84
Air and Water cooled inverter chillers and heat pump


Cause
Entering and leaving water temperature
normal sensors are inverted.
Entering and leaving water pipes are
reversed
Water pump operate reverse.



Cause
Outside ambient temperature is lower than
value set into unit's controller.
Improper operation of Outside Ambient
Temperature sensor.



Cause
Sensor is broken.
normal
Sensor is shorted.
Sensor is not properly connected (open).
Notes
Solution
Check cabling of the sensors on the unit
controller.
Check offset of the two sensors with the
water pump running
Check if the water flows in counter flow
respect to refrigerant.
Check if the water flows in counter flow
respect to refrigerant.
Notes
Solution
Check the minimum outside ambient
temperature value set into the unit's
controller.
Check if this value is in accordance with
chiller application, therefore check about
the proper application and utilization of the
chiller.
Check for proper operation of OAT sensor
according information about kOhm (k)
range related to temperature values.
Notes
It clears automatically with a 2.5°C of
hysteresis.
Solution
Check for sensor integrity.
Check correct sensors
according table and allowed kOhm (k)
range.
Check if sensor is shorted with a
resistance measurement.
Check for absence of water or humidity on
electrical contacts.
Check for correct plug-in of the electrical
connectors.
Check for correct sensors wiring also
according electrical scheme.
Notes
EWAD TZ - EWAD TZ B -EWWD VZ
Air and Water cooled inverter chillers and
heat pump
operation