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

SiEN12-710A
4.7

Freeze-up Protection Control

A5
Remote Control
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 control.
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 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, insufficient gas, and compressor lock.)
Supposed
" Wrong wiring or piping
Causes " EV malfunctioning in each room
" Short-circuit
" Indoor unit heat exchanger thermistor abnormality
" Room temperature thermistor abnormality
Service Diagnosis
Troubleshooting
117