R410A All DC Inverter V5 X Series 50Hz      MCAC-VTSM-2015-10 
14                                                                                                                                                                                          Selection Procedure 
1.  Introduction   
1.1  Model selection procedure 
Select the model and calculate the capacity for each refrigerant system according to the procedure shown 
below. 
  -conditioning load, Calculate the maximum air-conditioning load for each room 
or zone. 
Selection of air conditioning system 
   
Design of the control system 
   
Preliminary selection of indoor and outdoor units 
   
Check of the tubing length and level difference 
  Check that the length of refrigerant tubing and the elevation difference are within the allowable ranges 
Calculation of the corrected outdoor unit capacity 
  Capacity  correction  coefficient  for  model,  outdoor  temperature  conditions,  tubing  length  and  elevation 
difference. 
Calculation of the actual capacity for each indoor unit 
  Calculate the corrected indoor/outdoor capacity ratio, based on the corrected outdoor unit capacity and the 
total corrected capacity of all indoor units in the same system. 
Recheck of the actual capacity for each indoor unit 
  If the capacity is inadequate, reexamine the unit combinations. 
1.2 Indoor unit selection 
Enter INDOOR UNIT CAPACITY TABLES at given indoor and outdoor temperature. Select the unit with the 
nearest greater capacity to the given load. 
Note: 
Individual indoor unit capacity is affected by ODU selection. Actual capacity has to be calculated according to the outdoor unit 
capacity table. 
Calculation of actual capacity of indoor unit 
Because  the  capacity of  a  multi  air-conditioner  system  changes  according  to  the  temperature conditions, 
tubing length, elevation difference and other factors, select the correct model after taking into account the 
various correction values. When selecting the model, calculate the corrected capacities of the outdoor unit and 
each indoor unit. Use the corrected outdoor unit capacity and the total corrected capacity of all the indoor units 
to calculate the actual final capacity of each indoor unit. 
Find the indoor unit capacity correction coefficient for the following items: 
  Capacity correction for the indoor unit temperature conditions 
From  the  graph  of  capacity  characteristics,  use  the  indoor  temperature  to  find  the  capacity  correction 
coefficient. 
  Capacity distribution ratio based on the indoor unit tubing length and elevation difference. 
First, in the same way as for the outdoor unit, use the tubing length and elevation difference for each indoor 
unit to find the correction coefficient from the graph of capacity change characteristics 
Capacity distribution ratio for each indoor unit=Correction coefficient for that indoor unit / Correction coefficient for the 
outdoor unit 
1.3 Outdoor unit selection 
Allowable combinations are indicated in INDOOR UNIT COMBINATION TOTAL CAPACITY INDEX TABLE. 
In general, outdoor units should be selected by the following factors, the location of the unit, zoning and usage