Freeze-Up Protection Control - Daikin CTXS09GVJU Service Manual

SiUS12-814
5.9

Freeze-up Protection Control

A5
Remote
Controller
Display
Outdoor Unit LED A 5
Display
Method of
Indoor unit icing, during cooling operation, is detected by checking the temperatures sensed by the
Malfunction indoor unit heat exchanger thermistor and room temperature thermistor that are located in a 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 ≤ 30°F
Decision
(B) Indoor unit heat exchanger temperature ≤ Room temperature
Conditions
Supposed
Causes
Service Diagnosis
1 4 2 1 3 4 4 4
If the indoor unit icing protector is activated four times straight, the system will shut down.
(The 4-time counter will reset itself if any of the following errors does not occur during the
compressor running time (total time): OL, radiation fin temperature rise, gas shortage, and
compressor startup.)
<Total 60 minutes>
Wrong wiring or piping
EV malfunctioning in each room
Short-circuit
Indoor unit heat exchanger thermistor defective
Indoor unit thermistor defective
Troubleshooting
Δ
–18°F
125