Mitsubishi P192 User Manual

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VII  Control ]

- 108 -

HWE09120

GB

ŒDepending on the capacity required, the rotation speed of the outdoor unit fan is controlled by the inverter, targeting a constant 

evaporation temperature of (0°C [32°F]= 0.71 MPa [103 psi]) during cooling operation and constant condensing temperature 
of (49°C [120°F]= 2.88 MPa [418 psi]) during heating operation. 

ŒThe OS in the multiple-outdoor-unit system operates at the actual outdoor unit fan control value that is calculated by the OS 

based on the preliminary outdoor unit fan control value that the OC determines.

ŒOutdoor unit fan stops while the compressor is stopped (except in the presence of input from snow sensor).

ŒThe fan operates at full speed for 5 seconds after start-up.(Only when TH7<0°C [32°F])

ŒThe outdoor unit fan stops during defrost operation.

ŒOn the P120 and P144 models of outdoor units, before the second fan goes into operation, the capacity of the first fan is 

reduced to 50%.

ŒThe OC, OS1, and OS2 controls the subcool coil individually.

ŒThe LEV is controlled every 30 seconds to maintain constant the subcool at the outdoor unit heat exchanger outlet that is 

calculated from the values of high pressure (63HS1) and liquid piping temperature (TH3), or the superheat that is calculated 
from the values of low pressure (63LS) and the bypass outlet temperature (TH2) of the subcool coil.

ŒLEV opening is controlled based on the values of the inlet (TH6) and the outlet (TH3) temperatures of the subcool coil, high 

pressure (63HS1), and discharge temperature (TH4). In a single-outdoor-unit system, the LEV is closed (0) in the heating 
mode, while the compressor is stopped, and during cooling Thermo-OFF. In a multiple-outdoor-unit system, the LEV closes 
(0) during heating operation, while the compressor is stopped, or during cooling Thermo-OFF. The LEV opens to a specified 
position when 15 minutes have passed after Thermo-OFF. (65 pulses)

ŒDuring the defrost cycle, normally, the valve initially operates at 0 pulses, although it may operate at higher pulses depending 

on the 63LS and TH4 status.

ŒRefrigerant flow is controlled by each unit in the combined models during heating. Refrigerant flow control is performed by the 

OC, OS1, and OS2 individually. The valve opens to a specified angle during cooling (Opening: 2100 pulses)

ŒValve opening is controlled based on the values of high pressure (63HS1), discharge temperature (TH4), low pressure( 

63LS), and piping temperature (TH5). 

ŒThe valve moves to the predetermined position while the unit is stopped.

ŒThe valve opening may increase to 3000 pulses during the defrost cycle or when the units are operated in unusual operating 

conditions.

ŒWhen started up for the first time before 12 hours have elapsed after power on, the unit goes into the initial startup mode.

ŒAt the completion of the initial operation mode on the OC, OS1, and OS2, they will go into the normal control mode.

50     F     60Hz

or      F < 50Hz

Initial startup mode starts.

Completed in the integrated operation time of 35 minutes.

Initial startup mode complete

or the discharge superheat (TH4 - TC) is detected (within 
5 minutes of startup) that remains above  approximately 
20 degrees for one minute .

Completed in the integrated operation time of 90 minutes.