Control Specifications - Mitsubishi Electric PRH-P8MYA Technical & Service Manual

[2] Control specifications

(1) Protection functions
1) The main protection devices for the unit are:
a) High pressure protection (63H1)
b) Compressor overcurrent protection (51C)
c) Liquid temp thermistor trouble (TH1)
d) Discharge temperature protection (TH2 ≥118 °C)
e) Discharge temp thermistor trouble (TH2)
f) Condenser/evaporater temp thermistor trouble (TH3)
g) Low pressure protection (63L)
h) Inlet temp thermistor trouble (TH4)
i) Liquid temp thermistor trouble (TH5)
j) Condenser/evaporater temp thermistor trouble (TH6)
2) When tripping of a detection device is sensed, the check mode is entered and the compressor is stopped. (After 3
minutes, the compressor restarts.) Thereafter, the compressor is stopped when the specified number of check
modes or greater is sensed within the check time.
Protection functions
a) High pressure protection
(63H1)
b) Compressor overcurrent
protection (51C)
c) Liquid temp thermistor
trouble (TH1)
d) Discharge temperature
118 °C)
= >
protection (TH2
e) Discharge temp ther-
mistor trouble (TH2)
f) Condenser/evaporater
temp thermistor trouble
(TH3)
g) Low pressure protection
(63L)
h) Inlet temp thermistor
trouble (TH4)
i) Liquid temp thermistor
trouble (TH5)
j) Condenser/evaporater
temp thermistor
trouble (TH6)
3) Check mode is released by stopping operation, changing the operation mode, or check mode time up. A check
mode is also released by stopping of operation by remote controller.
4) Detected check mode history (newest) and abnormality history (last 2 times) are memorized and are displayed on
the segment by circuit board DIP switch setting.
The operation mode when the newest abnormality was generated, the thermistor temperature (TH1,2,3), and the
thermostat ON time can also be displayed.
Operation value
3.3 MPa Compressor operating
P8MYA: 22 A
Compressor operating
P10MYA: 27 A
Compressor operating except for
Less than –39 °C or
10 minutes at end of defrosting
greater than 88 °C
and 7 minutes while compressor
starting
Greater than 118 °C
Compressor operating
Compressor operating except for
Less than 0 °C or
10 minutes at end of defrosting
greater than 216 °C
and 5 minutes while compressor
starting
Compressor operating except for
Less than –39 °C or
10 minutes at end of defrosting
greater than 88 °C
and 7 minutes while compressor
starting
Compressor operating except for
0 MPa defrosting, 10 minutes at end of
defrosting
Less than –40 °C or
Cooling, heating operating
greater than 90 °C
Less than –40 °C or
Cooling, heating operating
greater than 90 °C
Less than –40 °C or
Cooling, heating operating
greater than 90 °C
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Detection condition
Number of
Check time
check modes
0 –
1 time 30 minutes
2 times 30 minutes
2 times 30 minutes
2 times 30 minutes
2 times 30 minutes
4 times
30 minutes
1 time 3 minutes
1 time
3 minutes
1 time 3 minutes