Si18-201 Troubleshooting - Split Type Indoor Unit
Service Diagnosis 233
1.5.2 Operation Halt Due to the Freeze Protection Function
Remote
Controller
Display
A5
Indoor Unit LED
Display
A
5
B
5
Note: No LED Display on FTK(X)25/35J Series.
Method of
Malfunction
Detection
"
High pressure control
During heating operations, the temperature detected by the indoor heat exchanger
thermistor is used for the high pressure control (stop, outdoor fan stop, etc.)
"
The freeze protection control (operation halt) is activated during cooling operation according
to the temperature detected by the indoor unit heat exchanger thermistor.
Malfunction
Decision
Conditions
"
High pressure control
During heating operations, the temperature detected by the indoor heat exchanger
thermistor is above 67°C
"
Freeze protection
When the indoor unit heat exchanger temperature is below 0°C during cooling operation.
Supposed
Causes
"
Operation halt due to clogged air filter of the indoor unit.
"
Operation halt due to dust accumulation on the indoor unit heat exchanger.
"
Operation halt due to short-circuit.
"
Detection error due to faulty indoor unit heat exchanger thermistor.
"
Detection error due to faulty indoor unit PCB.