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MUL
TI V Split Rooftop Unit Installation Manual
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Device Connection Limitations
When designing a system, the engineer must take into consideration the combination ratio.
Installation Options
Combination Ratio
MV Outdoor Unit (ODU) with only RTUs The total capacity of all RTUs must be 50-110% of ODU capacity.
MV ODU with RTUs and other indoor
units
• The total capacity of all indoor units (Indoor Unit + RTU) must be 50-100% of outdoor unit
capacity.
• The total capacity of RTUs must be less than 60% of the total capacity of all indoor units.
Failure to comply with the above connection conditions for installation can cause reduced heating/cooling performance.
Sample Layouts (Combination Ratio Examples)
Split RTU
6.0 Ton
Outdoor Unit
20.0 Ton
Split RTU
6.0 Ton
Indoor Unit
4.0 Ton
Indoor Unit
4.0 Ton
Combination Ratio
Split RTU
6.0 Ton
Outdoor Unit
20.0 Ton
Split RTU
6.0 Ton
Indoor Unit
4.0 Ton
Indoor Unit
6.0 Ton
Incorrect installation: Total capacity of indoor units
cannot exceed 100% of outdoor unit capacity.
Images are for illustrative purposes only and are not accurate representations. For specific details on piping limitations and other refrigerant system
rules, review the information in the appropriate Engineering or Installation Manual, and follow the LATS diagram.
Figure 7: RTU Correct Combination Ratio.
Figure 8: RTU Incorrect Combination Ratio.
INSTALLATION GUIDELINES