Mitsubishi Electronics MSY-A15/17/24NA Air Conditioner User Manual


 
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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 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.
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, the control stops the compressor.
When temperature of the discharge temperature thermistor is 176°F (2A/3A30NA/2B)/ 212°F (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, 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 and less than 240.8°F,
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 and less than 231.8°F,
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 155822257070
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