Daikin F401~F403

Alarm
Logic
  • F401 Supply air temperature sensor (SS) fault. And both DSS and RS fault
  • F403 Return air temperature sensor (RS) fault. And both DRS (option) and SS
Possible
Causes		 Unit can not be controlled due to backup operation is not available
  • Lead line of sensor is disconnected / Lead line is short circuited
  • Connector disconnected
  • Sensor failure
  • CPU board failure
Trouble
Shooting
  • Check sensor resistance value. (refer to sensor specifications table in page 6-2) Replace as needed
Controller
Action
  • F401 Unit stopped
  • F403 Unit stopped
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