Daikin EWAT_B - 5.1.7 HeatRec LvgWTempSen - Heat Recovery Leaving Water Temperature sensor fault (A;C units only); 5.1.8 HeatRec FreezeAlm - Heat Recovery Water Freeze Protect alarm (A;C units only); 5.1.9 Option1 BoardComm - Optional board 1 communication fail (A;C units only); 5.1.10 Option2 BoardComm - Optional board 2 communication fail

Operating Manual
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EWAT_B
Local HMI
Network
Auto
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5.1.7 HeatRec LvgWTempSen - Heat Recovery Leaving Water Temperature sensor fault (A/C units only)
This alarm is generated any time that the input resistance is out of an acceptable range.
Symptom
Cause
Solution
Heat Recovery is Off
Bell icon is moving on controller’s display.
String in the alarm list:
HeatRec LvgWTempSen
String in the alarm log:
 HeatRec LvgWTempSen
String in the alarm snapshot
HeatRec LvgWTempSen
Sensor is broken.
Check for sensor integrity.
according table and allowed kOhm (k)
range.
Check correct sensors operation
Sensor is shorted.
Check if sensor is shorted with a resistance
measurement.
Sensor is not properly connected (open).
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.
Reset
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5.1.8 HeatRec FreezeAlm - Heat Recovery Water Freeze Protect alarm (A/C units only)
This alarm is generated to indicate that the heat recovery water temperature (entering or leaving) has dropped below a
safety limit. Control tries to protect the heat exchanger starting the pump and letting the water circulate.
Symptom
Cause
Solution
Unit status is Off.
All circuits are stopped immediately.
Bell icon is moving on controller’s display.
String in the alarm list:
HeatRec FreezeAlm
String in the alarm log:
 HeatRec FreezeAlm
String in the alarm snapshot
HeatRec FreezeAlm
Water flow too low.
Increase the water flow.
Inlet temperature to the heat recovery is
too low.
Increase the inlet water temperature.
Sensors readings (entering or leaving) are
not properly calibrated
Check the water temperatures with a
proper instrument and adjust the offsets
Reset
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Network
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5.1.9 Option1BoardComm – Optional board 1 communication fail (A/C units only)
This alarm is generated in case of communication problems with the AC module.
Symptom
Cause
Solution
Unit status is Off.
All circuits are stopped immediately.
Bell icon is moving on controller’s display.
String in the alarm list:
Option1BoardComm
String in the alarm log:
 Option1BoardComm
String in the alarm snapshot
Option1BoardComm
Module has no power supply
Check the power supply from the
connector on the side of the module.
Check if LEDs are both green.
Check if the connector on the side is tightly
inserted in the module
Module address is not properly set
Check if module’s address is correct
referring to the wiring diagram.
Module is broken
Check if LED are on and both green. If
BSP LED is solid red replace the module
Check if power supply is ok but LEDs are
both off. In this case replace the module
Reset
Local HMI
Network
Auto

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5.1.10 Option2BoardComm – Optional board 2 communication fail
This alarm is generated in case of communication problems with the AC module.
Symptom
Cause
Solution
Unit status is Off.
All circuits are stopped immediately.
Bell icon is moving on controller’s display.
String in the alarm list:
Option2BoardComm
Module has no power supply
Check the power supply from the
connector on the side of the module.
Check if LEDs are both green.
Check if the connector on the side is tightly
inserted in the module