Enertech VS Series - Duct Work and Connections

10
Enertech Global IOM, VS/VT Models, Rev A
Typical Supply and Return Ductwork Connections
Flex Connectors
Supply Air
Dealer Provided
Indoor Air Quality
return duct system
SOURCE WATER IN
SOURCE WATER OUT
HOT WATER OUT
HOT WATER IN
CONDENSATE DRAIN
Dealer Provided
air duct system
Equipment Pad
2” Polyethylene Foam
NOTE: Maintain duct size of supply ange for at least
12” before transitioning to size of supply plenum
designed for duct system.
Duct Work
All new ductwork shall be designed as outlined
in Sheet Metal and Air Conditioning Contractors
National Association (SMACNA) or Air Conditioning
Contractors of America (ACCA) or American
Society of Heating, Refrigerating and Air
Conditioning Engineers (ASHRAE) handbooks. All YT
Models do not have more than 2% air leakage
All supply/return plenums should be isolated
from the unit by a exible connector (canvas) or
equivalent to prevent transfer of vibration noise
to the ductwork. The ex connector should be
designed so as not to restrict airow. Turning vanes
should be used on any transition with airow over
500 CFM. All metal ductwork should be insulated on
the inside to prevent heat loss/gain, condensation
and to absorb air noise. If the unit is being installed
with existing ductwork, the ductwork must be
designed to handle the air volume required by
the unit being installed. When running a cooling
or heating load on a building, size ductwork
accordingly to the building design load and heat
pump CFM.
Industry Standard: When sizing ductwork use 400
CFM per Ton.
As a general rule, maximum recommended face
velocity for a supply outlet used in a residential
application is 750 FPM. Maximum recommended
return grille velocity is 600 FPM. Systems with higher
velocity, are likely to have noise problems.
In buildings where ceilings are 8 feet or more, at
least 50 percent of the return air should be taken
back to the heat pump from the ceiling or high
sidewall location and not more than 50 percent
from the oor or low sidewall location.
Table 1: Maximum Air Velocities
Location Supply Return
Main Ducts 900 FPM 600 FPM
Branch Ducts 700 FPM 600 FPM
Grills, Registers, Diffusers 750 FPM 600 FPM
Section 3: Installation Considerations