Bulletin 100-135 / August 2010
Note — Specifications, Ratings, and Dimensions are subject to change without notice. Copyright© 2010 Heat Controller, Inc.
Installation Guide
This instruction is a summary of the basic rules and applies to most applications.
Duct Layout
Outlets
7 two inch outlets Per Ton / 5 two and a half inch outlets Per Ton (3.5 kW). For refrigerant cooling applications the
airflow must be between 200 and 250 CFM per nominal ton [27 to 33 L/s per nominal cooling kW]. For hot water or chilled
water systems, refer to performance charts for determine the required airflow. The allowable airflow range per 2 inch outlet
is 20 to 40 CFM [9.4 and 19 L/s] and 25 to 55 CFM [11.8 and 23.75 L/s], where the typical outlet will deliver 35 CFM [17
L/s] if the plenum static pressure is 1.5 inches [0.37 kPa] and the branch duct length is 10-foot (3 meter) without any
balancing orifices. Therefore, the average project will require about 7 2 inch outlets or 5 two and a half inch outlets per
nominal ton although more will be needed if the branch ducts are longer, balancing orifices are used, the plenum static
pressure is less than 1.5 inches of water [0.37 kPa], or it is desirable to make the system as quiet as possible. For example,
two runs with 50% balancing orifices are equal to one branch run without any orifices.
10% Rule. For supply ducts longer than 10 feet (3 meter), the air is reduced in that run by 10% for every 5 feet over 10
(every 1.5 meter over 3 meters). For example, a 30 foot [9 meter] run is 60% of an outlet that is 10 foot [3 m] yielding a
reduction of 40% (30-10=20, 20
5=4, 4
10=40%).
Consider Traffic Pattern. Place outlets out of traffic pattern. A corner, 5-inch [127 mm] from each wall, is a good location,
or along walls, or in soffits blowing horizontally. Consider floor outlets (with screens) for units located in basement. Slotted
outlets can be used for high wall locations or in ceilings where there is insufficient room for bending tubing.
Allow for Aspiration. Locate outlets so the air stream does not impinge on any objects or people — at least 3 feet [1 m]
away. Use outlet deflectors and outlet balancing orifices sparingly as they disrupt the aspiration.
Minimize Length, Minimize Restriction. Keep the supply duct length as close to 10 feet [3 m] as possible and never less
than 6 feet [1.8 meters]. Use the fewest number of bends as possible. Maximize the radius of any bends making sure the
bend in the sound attenuator tubing near the outlet is at least 6-inch [152 mm].
Plenum
Maximize Length, Minimize Restriction. Run main trunk (plenum) as long as possible; it is better to lengthen the plenum
if you can shorten even two outlet runs. Use full flow tees with turning vanes (when applicable) and full flow elbows. The
maximum total plenum length is 150 ft [45 m]; consider the first tee equal to 30 ft [9 m] and elbows equal to 15 ft [4.6 m].
60/40 Rule. When using a tee split the flow as close to 50/50 as possible — no more than 60/40. Always use a turning vane.
70/30 Rule. Turn the tee 90° to make a side branch with no more than 30 percent of the air. Do not use a turning vane
Horseshoe Patterns. (Best Method). Use a tee at least 24 inches [610 mm] off unit. For the 4860 unit, use 10-inch [254
mm] metal up to and including tee; then use 9-inch [229 mm] both directions. For the 3642 unit, use 9-inch [229 mm]
insulated metal up to and including tee; then use 7-inch [178 mm] both directions. If possible, close the horseshoe into a
perimeter loop.
PERIMETER LOOP SYSTEM
IL00121.CVS
HORSESHOE SYSTEM
IL00122.CVS
DOGLEG SYSTEM IL00123.CVS
'H' SYSTEM
IL00125.CVS
