31
3-4. HEAT DEFROSTING CONTROL
(1) Starting conditions of defrosting
When the following conditions a) ~ c) are satisfied, the defrosting starts.
a) The defrost thermistor reads 26.6°F (-3°C) or less.
b) The cumulative operation time of the compressor has reached any of the set values (defrost interval: 40-150 min-
utes).
c) More than 5 minutes have passed since the start-up of the compressor.
The defrost interval is decided by the previous defrosting time. The next defrost interval extends or shortens 0-20
minutes compared with the previous defrost interval.
(2) Releasing conditions of defrosting
Defrosting is released when any one of the following conditions is satisfied:
a) The defrost thermistor continues to read 50.7°F (10.4°C).
b) Defrosting time exceeds 10 minutes.
c) Any other mode than HEAT mode is set during defrosting.
3-5. DISCHARGE TEMPERATURE PROTECTION CONTROL
This protection controls the compressor ON/OFF and operation frequency according to temperature of the discharge tempera-
ture thermistor.
(1) Compressor ON/OFF
When temperature of the discharge temperature thermistor exceeds 240.8°F (116°C), the control stops the compressor.
When temperature of the discharge temperature thermistor is 176°F (80°C) (
2A
/
3A30NA/2B
)/ 212°F (100°C) (
3A30NA-
1
/
4A/3B/4B
) or less, the controls starts the compressor.
(2) Compressor operation frequency
When temperature of the discharge temperature thermistor is expected to be higher than 240.8°F (116°C), the control
decreases 12 Hz from the current frequency.
When temperature of the discharge temperature thermistor is expected to be higher than 231.8°F (111°C) and less than
240.8°F (116°C), the control decreases 6 Hz from the current frequency.
When temperature of the discharge temperature thermistor is expected to be higher than 219.2°F (104°C) and less than
231.8°F (111°C), the control is set at the current frequency.
MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA
Number of operating
unit
Capacity code
COOL (Hz)
DRY (Hz)
HEAT (Hz)
Min. Max.
Min. Max.
Defrost
1
3,4
15
58
22
25
70
70
7
15
58
22
25
70
70
9,10
15
71
31
25
80
80
12
15
80
42
25
80
80
2
5 ~ 7
25
80
35
35
80
80
8 ~ 10
25
80
35
35
80
80
11 ~ 13
25
80
35
35
80
80
14 ~ 16
25
80
35
35
80
80
17 ~
25
80
52
35
80
80
3 (
MXZ- 3B
)
9 ~
52
80
52
39
80
80
3 (
MXZ-4B
)
9 ~
52
90
52
39
103
80
4 (
MXZ-4B
)
12 ~
62
90
70
52
113
80
Summary of Contents for MS-A WA
Page 39: ...39 ...
