Freeze-Up Protection Control - Daikin G-Series Service Manual

SiBE12-933_A
4.7

Freeze-up Protection Control

A5
Remote
Controller
Display
Method of Indoor unit icing, during cooling operation, is detected by checking the temperatures sensed by
the indoor unit heat exchanger thermistor and room temperature thermistor that are located in a
Malfunction
shut-down room.
Detection
At another room (the indoor unit is normal), " UH " is displayed on the remote controller.
Malfunction In the cooling mode, the following conditions (A) and (B) are kept together for 5 minutes.
(A) Indoor unit heat exchanger temperature ≤ –1°C
Decision
(B) Indoor unit heat exchanger temperature ≤ Room temperature –10°C
Conditions
If the freeze-up protection control is activated 4 times continuously, the system is shut down.
(The 4-time counter is reset if any of the following errors does not occur for 60 minutes.
: OL, radiation fin temperature rise, refrigerant shortage, and compressor lock.)
Supposed
Causes
Service Diagnosis
Wrong wiring or piping
Electronic expansion valve malfunctioning in each room
Short-circuit
Indoor unit heat exchanger thermistor abnormality
Room temperature thermistor abnormality
Troubleshooting
183