Mitsubishi Heavy Industries SRK100VNXPZSX Technical Manual page 186

(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 of item 2), a) is established during the compressor protection start III, E49
is displayed at initial stop and it enters the anomalous stop mode.
(f) Compressor pressure ratio protection control
(i) During heating operation, if the indoor unit heat exchanger temperature (Th2) and the 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 unit fan.
(iii) This control is not performed during defrost operation and at 10 minutes after the reset of defrost operation.
(iv) When there are 3 indoor unit heat exchanger temperatures (Th2), the highest temperature is detected.
65
°C
33 °C
0.150
(g) Over-current protection current safe controls I, II
Detecting the outdoor unit inverter input (primary) current and the output (secondary) current, if the current values exceed
setting values, the compressor speed (frequency) is controlled to protect the inverter.
Reduces frequency
Retention
Reset
B A
Current (A)
(Fig. C) The control value "A" and the reset value vary depending
on the compressor speed.
24
22
20
18
16
Reset valve B
14
12
40 50 60
Compressor speed (frequency) (rps)
Retention
0.150 0.189
Low pressure (MPa)
Reduces compressor frequency at each minute.
Resert
0.425
Low pressure (MPa)
at each minute.
Control valve A
70 80 90 100 110 120 130
-
Reset
Model
Control
value A
Primary
FDC100, 125,
current 13.5 (23.0) 12.5 (22.0) 13.5 (23.0) 12.5 (22.0)
140
side
Secandary
FDC100, 125,
current 13.0 (Fig.C) 12.0 (Fig.C) 13.0 (Fig.C) 12.0 (Fig.C)
140
side
Note (1) Value in ( ) are for the single phase models.
185
-
'17 • PAC-T-257
Cooling Heating
Reset Control
value B value A value B
Reset