Mitsubishi SRK50ZHX-S Technical Manual page 21

(8) Compressor overheat protection
(a) Purpose: It is designed to prevent deterioration of oil, burnout of motor coil and other trouble resulting from the compressor
overheat.
(b) Detail of operation
1) Speeds are controlled with temperature detected by the sensor mounted on the discharge pipe.
(Example) Fuzzy
Notes (1) When the discharge pipe temperature is in the range of 105~115ºC, the speed is reduced by 4 rps.
(2) When the discharge pipe temperature is raised and continues operation for 20 seconds without changing, then the speed is reduced again by 4 rps.
(3) If the discharge pipe temperature is in the range of 95~105ºC even when the inverter command speed is maintained for 3 minutes when the
temperature is in the range of 95~105 ºC, the speed is raised by 1 rps and kept at that speed for 3 minutes. This process is repeated until the
command speed is reached.
(4) Lower Limit Speed
Lower Limit Speed
2) If the temperature of 115ºC is detected by the sensor on the discharge pipe, then the compressor will stop immediately.
When the discharge pipe temperature drops and the time delay of 3 minutes is over, the unit starts again within 1 hour but
there is no start at the third time.
(9) Current safe
(a) Purpose: Current is controlled not to exceed the upper limit of the setting operation current.
(b) Detail of operation: Input current to the converter is monitored with the current sensor fixed on the printed circuit board
(10) Current cut
(a) Purpose: Inverter is protected from overcurrent.
(b) Detail of operation: Output current from the inverter is monitored with a shunt resistor and, if the current exceeds the
(11) Outdoor unit failure
This is a function for determining when there is trouble with the outdoor unit during air conditioning.
The compressor is stopped if any one of the following in item 1), 2) is satisfied. Once the unit is stopped by this function, it is not
restarted.
1) When the input current is measured at 1 A or less for 3 continuous minutes or more.
2) If the outdoor unit sends a 0 rps signal to the indoor unit 3 times or more within 20 minutes of the power being turned on.
(12) Indoor fan motor protection
When the air conditioner is operating and the indoor fan motor is turned ON, if the indoor fan motor has operated at 300 rpm or
under for more than 30 seconds, the unit enters first in the stop mode and then stops the entire system.
After lapse of 3 min. or over
After lapse of 3 min. or over
After lapse of 3 min. or over
95
Discharge pipe temperature (˚C)
Cooling Heating
25 rps 32 rps
of the outdoor unit and, if the operation current value reaches the limiting current value, the inverter
command speed is reduced.
If the mechanism is actuated when the inverter command speed is less than 30 rps, the compressor is
stopped immediately. Operation starts again after a delay time of 3 minutes.
setting value, the compressor is stopped immediately. Operation starts again after a delay time of 3
minutes.
(3)
(3)
Lower limit
(3)
105
18
- -
(1)
4 rps
4 rps
(4)
0 rps
115