Hitachi UTOPIA RAS-4HVRP2E - Page 274

10 Troubleshooting
Troubleshooting procedure
SMGB0136 rev.0 - 07/2021
272
Alarm code
13
Abnormality of Thermistor for Liquid Refrigerant Pipe Temperature at Indoor Unit Heat Exchanger
(Freeze Protection 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 Freeze
Protection Thermistor
Failure of Indoor Unit PCB
Failure
Incorrect Connection
Check resistance
Check wiring to Indoor Unit PCB
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 THM3
between0.24kΩand840kΩ?
Is thermistor THM3 (for freeze
protection) connected to
THM3 of indoor Unit PCB?
Yes
Yes
No
No
Connect them
Refer to “Alarm Code 11”
for thermistor resistance