SiSG121917E
Control Specification
Part 4 Functions and Control
82
4.6 Freeze-up Protection Control
4.6.1 Freeze-up Protection Control for Wall Mounted and LSP Duct Type
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 2
seconds after operation starts and 30 seconds after the number of operation room is changed.
4.6.2 Freeze-up Protection Control for MSP Duct Type
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.
The indoor heat exchanger temperature remains at
A
°C or lower for 1 minute.
The accumulated time that the indoor heat exchanger temperature remains at
B
°C or lower
reaches 40 minutes.
Accumulated timer clearing condition
The indoor heat exchanger temperature remains at
C
°C or higher for 20 minutes.
Ending condition
The indoor heat exchanger temperature remains at
D
°C or higher for 10 minutes.
R4003618
A
(°C)
B
(°C)
C
(°C)
11
10.5
10
(R23581)
Reset zone
Indoor heat exchanger
temperature
Up zone
Keep zone
Dropping zone
Stop zone
0˚C
C
˚C
B
˚C
A
˚C
13˚C
A
(°C)
B
(°C)
C
(°C)
D
(°C)
–5
–1
4
7
D
(°C)
A
(°C)
B
(°C)
C
(°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.
