Mitsubishi Heavy Industries FDUA160AVSAVH Service Manual page 33

(c) Switching of defrost control with SW3-1
(i) If SW3-1 on the outdoor unit control PCB is turned to ON, it becomes easier to enter the defrost operation. Use this
when installing a unit at snowing regions.
(ii) Control contents
1) It allows entering the defrost operation under the defrost condition A when the cumulative heating operation time
becomes 30 minutes. It is 37 minutes at SW3-1 OFF (Factory default).
2) It allows entering the defrost operation under the defrost condition B when the cumulative heating operation time
becomes 25 minutes. It is 30 minutes at SW3-1 OFF (Factory default).
3) It allows the defrost operation with the outdoor heat exchanger temperature (Tho-R) and suction pressure saturation
temperature (SST) being higher than normal.
(6) Protective control/anomalous stop control by compressor's number of revolutions
(a) Compressor discharge pipe temperature protection
(i) Protective control
As the discharge pipe temperature (detected with Tho-D) exceeds the setting value, the compressor speed (frequency)
is controlled to suppress the rise of discharge pipe temperature.
(ii) Anomalous stop control
1) If the discharge pipe temperature (detected with Tho-D) exceeds the setting value, the compressor stops.
2) When it is detected 2 times within 60 minutes or after continuous 60 minutes, including the stop of compressor, E36
is displayed on the remote control and it enters the anomalous stop mode.
(iii) Reset of anomalous stop mode
As it drops to the reset value of 90°C or lower for 45 minutes continuously, it becomes possible to restart from the
remote control.
(b) Cooling high pressure protection
(i) Protective control
1) Outdoor heat exchanger temperature (Tho-R) exceeds the setting value A.
2) When the outdoor air temperature (Tho-A) is 40°C or higher and outdoor heat exchanger temperature (Tho-R) exceeds
certain value. (depends on compressor frequency.).
3) Control value A is updated to an optimum value automatically according to the operating conditions.
(ii) Anomalous stop control
1) As the outdoor heat exchanger temperature (Tho-R) exceeds the setting value, the compressor stops.
2) If it is detected 5 times within 60 minutes or 65°C or higher continues for 60 minutes, including the stop of
compressor, E35 is displayed on the remote control and it enters the anomalous stop mode.
(iii) Reset of anomalous stop mode
As it reaches the reset value of 51°C or lower, it becomes possible to restart from the remote control.
Retention
Release
105
Discharge pipe temperature (°C)
Compressor operation
90
Discharge pipe temperature (°C)
Reduces compressor
speed at each minute.
Reset
A
Outdoor heat exchanger temperature (°C)
Compressor operation
51
Outdoor heat exchanger temperature (°C)
32
-
Reduces compressor
speed at each minute.
110
Compressor stop
135
Control value A
60-54°C
Compressor stop
65
-
'21 • PAC-SM-398