Technical Data Manual

Design of 3WAY VRF SYSTEM
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1. Model Selecting and Capacity Calculator
Refrigerant Charge Amount at Shipment (for outdoor unit)
DC
(oz)
U-96MF1U9
U-96MF1U9E
416
U-72MF1U9
U-72MF1U9E
416
System Limitations
3Max. No. allowable connected outdoor units
*1
Max. capacity allowable connected outdoor units 288,000 BTU/h (24-Ton, 84 kW)
40Max. connectable indoor units
50 – 130 %Max. allowable indoor/outdoor capacity ratio
*1: Up to 3 units can be connected if the system has been extended.
Additional Refrigerant Charge
Additional refrigerant charge amount is calculated from the liquid tubing total length as follows.
Further charge a certain amount listed below in addition to the amount of refrigerant charge.
Amount of Refrigerant Charge Per ft., According to Liquid Tubing Size
Liquid tubing size
(in. (mm))
Amount of refrigerant
charge (oz/ft.)
ø1/4" (ø6.35)
ø3/8" (ø9.52)
ø1/2" (ø12.7)
ø5/8" (ø15.88)
ø3/4" (ø19.05)
ø7/8" (ø22.22)
0.279
0.602
1.38
1.99
2.78
3.93
Required amount of additional refrigerant charge = [(Amount of
additional refrigerant charge per ft. of each size of liquid tube ×
its tube length) + (...) + (...)] + [Necessary amount of additional
refrigerant charge per outdoor unit + (...) + (...)]
* Always charge accurately using a scale for weighing.
Table 2-1-1 Necessary Amount of Refrigerant Charge Per Outdoor Unit
U-72MF1U9
U-72MF1U9E
42 oz/unit
U-96MF1U9
U-96MF1U9E
42 oz/unit
If the tubing length (LA) is less than 16.4 feet, it is necessary to add 71 oz/unit of refrigerant in addition to 42 oz.
NOTE
TD831158-02_3WAY_VRF_SYS.indb 5TD831158-02_3WAY_VRF_SYS.indb 5 2013/06/18 11:46:312013/06/18 11:46:31