Troubleshooting
4-26
4-4-2. Indoor temperature sensor error (E121)
Yes
No
No
In this case, is the resistance
value out of range in the temperature
table on the right?
Yes
Is indoor temperature
sensor disconnected from the
connector in PCB?
Restart the system after replacing the PCB
Restart the system after connecting
to the PCB connector
Indoor temperature sensor
failure (replace)
Remove the indoor temperature sensor
connector from the PCB and measure the
resistance between two terminals
Current
temperature(°C)
Resistance
(kΩ)
40
5.800
35
6.900
30
8.300
25
10.00
20
12.10
15
14.70
10
18.00
5
22.00
0
28.30
-5
33.90
-10
42.30
<Temperature sensor resistance value>
Indoor unit display
360 Cassette
x(Ice blue) x(Yellow green) x(Blue)
◑
(Red)
Judgment method
Refer to checking method, as shown below.
Symptom
If the indoor temperature sensor is open or short circuit.