Multi F Engineering Manual
Qidu(combi) = Qodu(rated) x Qidu(rated)
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EQUIPMENT SELECTION PROCEDURE
Using the System Combination Tables
Multi F system combination tables illustrate how each indoor unit receives a percentage of total outdoor unit rated capacity. Allocation is
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• Combinations of Non-Ducted Indoor Units
• Combinations of Ducted Indoor Units
• Combinations of Mixed Non-Ducted and Ducted Indoor Units
Multi F MAX system combination tables only show the total connected indoor unit capacity, but individual indoor unit capacity can be
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A more accurate method to determine expected capacity would be to apply the outdoor unit’s corrected capacity instead of rated capacity.
7DEOH Multi F / Multi F with LGRED Outdoor Unit (Multiple Piping) to Indoor Unit Refrigerant Line Length Derates.
Piping Length (feet) Cooling Capacity (%) Heating Capacity (%)
7,000 Btu/h Indoor Unit Models
25.0 100.0 100.0
32.8 98.4 99.2
49.2 95.8 97.8
65.6 93.2 96.4
82.0 90.6 95.0
9,000 Btu/h Indoor Unit Models
25.0 100.0 100.0
32.8 98.0 99.0
49.2 94.8 97.4
65.6 91.6 95.8
82.0 88.4 94.2
12,000 Btu/h Indoor Unit Models
25.0 100.0 100.0
32.8 97.6 98.6
49.2 93.8 96.4
65.6 89.9 94.1
82.0 86.1 91.9
15,000 Btu/h Indoor Unit Models
25.0 100.0 100.0
32.8 97.2 98.2
49.2 93.0 95.4
65.6 88.8 92.6
82.0 84.6 89.8
18,000 Btu/h Indoor Unit Models
25.0 100.0 100.0
32.8 98.6 99.6
49.2 96.4 99.0
65.6 94.1 98.3
82.0 91.9 97.7
24,000 Btu/h Indoor Unit Models
25.0 100.0 100.0
32.8 98.2 99.2
49.2 95.4 98.0
65.6 92.4 96.6
82.0 89.6 95.4
Capacity Coefficient Factors
Refrigerant Line Length Derates
For air-cooled systems, a capacity correction factor will have to be applied to account for the length of the system’s refrigerant pipe. Rate of
change in capacity due to increased piping lengths is shown in the tables below and on the next page.
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APPLICATION GUIDELINES | 189
Application Guidelines
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