Subcool Coil Control (Linear Expansion Valve Lev1); Refrigerant Flow Control; Control At Initial Start-Up - Mitsubishi Electric PUHY-P200 Service Handbook
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Also See for PUHY-P200:
- Service handbook (334 pages) ,
- Service handbook (182 pages) ,
- Service handbook (40 pages)
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[ VII Control ]
Subcool Coil Control (Linear Expansion Valve )
-10- Subcool Coil Control (Linear Expansion Valve )
The OC, OS1, and OS2 controls the subcool coil individually.
The 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.
LEV 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)
During 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.
Refrigerant flow control (Linear expansion valve )
-11- Refrigerant flow control (Linear expansion valve )
Refrigerant 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)
Valve opening is controlled based on the values of high pressure (63HS1), discharge temperature (TH4), low pressure(
63LS), and piping temperature (TH5).
The valve moves to the predetermined position while the unit is stopped.
The valve opening may increase to 3000 pulses during the defrost cycle or when the units are operated in unusual operating
conditions.
Control at Initial Start-up
-12- Control at Initial Start-up
When started up for the first time before 12 hours have elapsed after power on, the unit goes into the initial startup mode.
At the completion of the initial operation mode on the OC, OS1, and OS2, they will go into the normal control mode.
1. Flowchart of initial operation
(1) (E)P200, (E)P250, (E)P300, P350, P400, P450 models
HWE10040
Initial startup mode starts.
50
F
60Hz
Completed in the integrated operation time of 35 minutes.
or
F < 50Hz
Completed in the integrated operation time of 90 minutes.
Initial startup mode complete
- 98 -
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