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

[2] Control specifications

(1) Protection functions
1) The main protection devices for the outdoor 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)
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)
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.
(2) Compressor, 4-way valve, and crankcase heater control
1) Determines the operation mode and operates the compressor based on the indoor/outdoor communication or M-
NET communication data.
2) Compressor control has a function which prevents the compressor from restarting within 3 minutes.
3) The 4-way valve is always ON during heating (except during defrosting). In other modes, it is OFF. However, when
the operation mode was changed from heating to stop, the 4-way valve is turned off 10 minutes after the compres-
sor was stopped.
4) While the compressor is stopped, the crankcase heater remains ON. (OFF while the compressor is operating.)
5) When the operation mode is changed while the compressor is operating, the compressor stops and 3 minutes later
restarts in the new mode.
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
–23–
Detection condition
Number of
Check time
check modes
0 –
1 time 30 minutes
1 time 30 minutes
2 times 30 minutes
1 time 30 minutes
1 time 30 minutes
2 times 30 minutes