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

Troubleshooting
5.10

Freeze-up Protection Control

A5
Remote
Controller
Display
Outdoor Unit LED A
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
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
Supposed
Causes
222
1 2 3 4
5 4 1 4
If the freeze-up protection control is activated 4 times continuously, the system will be shut
down.
(The 4-time counter will reset itself if any of the following errors does not occur for 60
minutes: OL, radiation fin temperature rise, gas shortage, and compressor startup.)
Wrong wiring or piping
EV malfunctioning in each room
Short-circuit
Indoor unit heat exchanger thermistor defective
Room temperature thermistor defective
4
Si12-619A
Service Diagnosis