Service Manual

Control Specification SiUS071735E
35 Functions and Control
2.6 Freeze-up Protection Control
Outline During cooling operation, the signal sent from the indoor unit determines the frequency upper limit
and prevents the indoor heat exchanger from freezing.
Details When the freeze-up protection control starts, the compressor stops, the airflow rate is fixed to L tap,
and the drain pump turns ON. Conditions for starting and ending are as below.
Starting conditions
The freeze-up protection control starts when any of the following conditions is satisfied.
z The indoor heat exchanger temperature remains at A or lower for 1 minute.
z The accumulated time that the indoor heat exchanger temperature remains at B or lower
reaches 40 minutes.
Accumulated timer clearing condition
z The indoor heat exchanger temperature remains at C or higher for 20 minutes.
Ending condition
z The indoor heat exchanger temperature remains at D or higher for 10 minutes.
(°C) (°F)
A –5 23.0
B –1 30.2
C 439.2
D 744.6
D
A
B
C
Indoor heat
exchanger
temperature
The control starts.
The control starts.
The control ends
and the accumulated timer is cleared.
The accumulated timer is cleared.