Mitsubishi Electric CITY MULTI PUHY-400YMF-C Service Handbook page 100

(10) Liquid Distribution Control (electronic expansion valve (LEV2) constant capacity unit only)
• Liquid distribution control refers to the process by which liquid refrigerant returning from the constant and variable
capacity units during heating is equally distributed, and the opening of the constant capacity unit LEV2 is
so that there is no deficiency of liquid refrigerant in the accumulator of each unit.
adjusted
1 Distribution occurs during heating operations when both the variable and constant capacity units are in operation.
When the constant capacity unit is stopped, the LEV2 opening = 60.
2 The LEV2 opening is set to a standard which varies depending on the current operation frequency.
3 The levels of the superheating level (SH1) of the variable capacity unit TH2 and TH10 (whichever temperature is
higher) and the accumulator liquid level (AL1) are compared to the superheating level (SH2) of the constant
capacity unit TH9 and TH10a and the accumulator liquid level (AL2) to correct the standard opening of the LEV2
in 2 above.
Superheating Level
SH1 > 3
Variable
Capacity Unit
SH1
* Even when the constant capacity unit is stopped, the after-mentioned liquid refrigerant correction control operation may
control LEV2 operations. After the power source has been turned on, and before the variable capacity unit compressor
begins operation, the LEV2 is opened to 200. (After compressor operation begins, LEV2 = 60)
Chart: Corrections to the Standard LEV2 Opening
Accumulator Level
AL = 0 or 1
AL = 2
AL = 0 or 1
3
AL = 2
60 200
Range of Corrections to LEV2 Opening
Constant Capacity Unit
SH2 > 3
AL = 0 or 1 AL = 2
no change
no change
opening up opening down
no change
Standard LEV2 Opening
-97-
SH2 3
AL = 0 or 1 AL = 2
opening down
opening up no change
no change opening down
opening up no change
2000