Roof Ductwork Configuration - LG MULTI V ARNU363DDA4 Installation Manual

ROOF DUCTWORK CONFIGURATION

Roof Ductwork Configuration
When the supply air discharge opening and/or the return air intake opening are located on the bottom of a unit, the ductwork must be
connected to the curb directly. The actual opening sizes in the floor of the unit are not specified as they are slightly undersized from the duct
dimensions shown on the following curb drawings.
The contractor is responsible for providing transitions to accommodate difference in sizing between the unit and the building ducts. Duct
connections to collar-type openings can be made with S-cleats or overlapping joints. Apply caulk around each duct connection. Failure to
seal duct connections can cause air leakage and system performance problems.
A straight duct for a distance of three (3) to six (6) duct diameters from the unit discharge should be used to develop a full dynamic head.
Branching and turning closer to the discharge causes system effect losses.
When an air duct which carries supply air or warm air passes through a combustible roof, a clearance of one inch must be maintained between the
outside perimeter of ductwork and any combustible materials, per NFPA Standard 90A.
Access Holes (Bottom side)
A number of pre-punched holes / openings are provided on the cabinet for electrical and gas connections for each unit.
Figure 21: Split Rooftop Unit Access Holes
6.6
2.7 1.3
1.1
4.9 3.0
36
4.6
6.8
Due to our policy of continuous product innovation, some specifications may change without notification.
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[Unit: Inch]