Mitsubishi Heavy Industries V Multi FDC71VNX Technical Manual page 130

(c) Heating high pressure protection
(i) Protective control
1) As the indoor heat exchanger temperature (Thi-R) exceeds the setting value, the compressor speed (frequency) is
controlled to suppress the rise of high pressure.
2) Control value A is updated to an optimum value automatically according to the operating conditions.
Reduces compressor frequency
at every 30 seconds.
Reset
A
Indoor heat exchanger temperature (°C)
(ii) Anomalous stop control
Operation control function by the indoor unit control - See the heating overload protection, page 18.
(iii) Adaptation to existing piping, stop control
If the existing piping adaptation switch, SW5-1 (model FDC71: SW8-1), is turned ON, the compressor stops to
protect existing piping when the indoor heat exchanger temperature (Thi-R) exceeds the setting value.
Reset
Indoor heat exchanger temperature (°C)
(d) Anomaly detection control by the high pressure switch (63H1)
(i) If the pressure rises and operates the high pressure switch (opens at 4.15MPa/closes at 3.15MPa), the compressor stops.
(ii) Under any of the following conditions, E40 is displayed and it enters the anomalous stop mode.
1) When it occurs 5 times within 60 minutes that pressure rises and the compressor is stopped by 63H1.
2) When 63H1 has been in the open state for 60 minutes continuously, including the stop of compressor.
(e) Low pressure control
(i) Protective control
If the value detected by the low pressure sensor (LPT) exceeds the setting value, the compressor speed (frequency) is
controlled to restrain the drop of pressure.
Reduces compressor frequency
at every 30 seconds.
(ii) Anomalous stop control
1) When a value detected by the low pressure sensor (LPT) satisfies any of the following conditions, the compressor
stops to run for its protection.
a) When the low pressure drops to 0.079MPa or under for 15 seconds continuously.
b) At 10 minutes after the start of compressor, the suction overheat becomes 30°C and the low pressure becomes
0.15MPa or under for 60 seconds continuously.
2) E49 is displayed under any of the following conditions and it enters the anomalous stop mode.
a) When the low pressure drops 3 times within 60 minutes and the compressor stops under any of the above conditions.
b) When a value detected with the low pressure sensor becomes 0.079MPa or under for 5 minutes, including the
stop of compressor.
3) However, when the control condition 1). a) is established during the compressor protection start III, E49 is
displayed at initial stop and it enters the anomalous stop mode.
Compressor pressure ratio protection control (Model FDC100 - 140 only)
(f)
(i) During heating operation, if the indoor heat exchanger temperature (Thi-R) and low pressure sensor (LPT) exceed
the setting values at 10 minutes after the start of compressor, the compressor speed (frequency) is controlled to
protect the compressor.
(ii) This control is not performed during the outdoor fan ON and for 10 minutes from the start of outdoor fan.
(iii) This control is not performed during defrost operation and at 10 minutes after the reset of defrost operation.
(iv) When there are 2 indoor heat exchanger temperatures (Thi-R), the highest temperature is detected.
65
°C
33 °C
0.150
Compressor stop
47 58
Retention
0.150 0.189
Low pressure (MPa)
Reduces compressor frequency at each minute.
Resert
0.425
Low pressure (MPa)
129
-
Existing piping adaptation switch: SW5-1 (SW8-1: model FDC71)
Model
FDC71
FDC100-140
Note (1) Adaptation to existing piping is at ON.
Reset
-
'19 • PAC-T-327
OFF (Shipping) ON
Control value A (°C)
52-58
46-52
48-54