Hitachi UTOPIA RAS-4HVRP2E - Page 272

10 Troubleshooting
Troubleshooting procedure
SMGB0136 rev.0 - 07/2021
270
Alarm code
11
Abnormality of Thermistor for Indoor Unit Inlet Air Temperatures (Inlet Air Thermistor)
• Thealarmcodeisashedonthe7-segmentdisplayoftheoutdoorunit.
• The alarm code is displayed on the wired controller of the indoor unit.
Thisalarmcodeisdisplayedwhenashortcircuit(0.24kΩorless)ordisconnection(840kΩormore)ofthethermistoris
detected during a heating or cooling operation. The operation automatically restarts when the malfunction is removed.
Phenomenon
Cause
Check Item
Action (Turn OFF
Main Switch)
Failure of Inlet Air
Thermistor
Failure of Indoor Unit PCB
Failure
Incorrect Connection
Check resistance
Check connection
Replace Indoor Unit PCB and
check operation
Replace thermistor if faulty
Correctly connect wires
Replace Indoor Unit PCB if
faulty
Failure of Thermistor
Failure of Indoor Unit PCB
Is resistance of THM1
between0.24kΩand840kΩ?
Is thermistor THM1 (for inlet
air temperature) connected to
THM1 of indoor Unit PCB?
Yes
Yes
No
No
Thermistor
Resistance R
T
[kΩ]
Temperature T (°C)
Thermistor Characteristics
Connect them