Hitachi UTOPIA RAS-4HVRP2E - Page 276

10 Troubleshooting
Troubleshooting procedure
SMGB0136 rev.0 - 07/2021
274
Alarm code
15
Abnormality of Thermistor for Outside Air Temperature (for Econofresh)
• 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 Thermistor
for Outside Air
Temperature
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 THM4 (for
Outside Air Temperature)
between0.24kΩand840kΩ?
Yes
No
Refer to “Alarm Code 11”
for thermistor resistance