Freeze-Up Protection Control - Daikin CTX Series Service Manual

Control Specification
3.6

Freeze-up Protection Control

Outline During cooling operation, the signals sent from the indoor unit control the operating frequency
limitation and prevent freezing of the indoor heat exchanger. The signal from the indoor unit is
divided into zones.
Details
The operating frequency limitation is judged with the indoor heat exchanger temperature.
 Frequency control in each zone
Reset zone
Up zone
Keep zone
Dropping zone
Stop zone
All outdoor units
All outdoor units
38
13°C (55.4°F)
Reset zone
A°C (°F)
Up zone
B°C (°F)
Keep zone
C°C (°F)
Dropping zone
0°C (°F)
Stop zone
Zone
The upper limit of frequency is cancelled
The upper limit of frequency increases
The upper limit of frequency is kept
The upper limit of frequency decreases
When indoor coil temperature <0°C for >80s, compressor is stopped
A (°C)
7.0
A (°F)
44.6
Indoor heat exchanger
thermistor temperature
Control
B (°C) C (°C)
5.0 3.0
B (°F) C (°F)
41.0 37.4
DAMA-SM-21-003
Functions and Control