Oasys SEER 40 PLUS Owner's Manual - page 17

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16

InSTAllATIOn InSTruCTIOnS continued

exhaust fan discharge,  plumbing drainage system vent, chimney outlet, or other source of con-

taminated air unless the outlet is more than 3’ above the cooler intake.

•  For non-ducted systems, locate the unit so that it discharges air into common spaces such as 

living rooms or hallways, but not so that it will create substantial drafts in seating areas.  The air 

supply should be at least 5’ above the floor.

•  For ducted systems, duct connections should be as short as possible.  Be sure to allow adequate 

space for duct connections (see below).

•  All systems require an air relief path, either into the attic through barometric dampers, or to the 

exterior.  Plan the installation so that air can travel freely from the OASys to the discharge open-

ings.

•  The unit must be fully accessible for service (see clearance requirements, Fig 4.)

PLANNING FOR AIR DISTRIbUTION 

UNLIKE REFRIGERANT-bASED AIR CONDITIONERS, which use multiple supply air outlets 

to distribute cooling and one return air inlet, OASys systems can be installed with one or two supply air 

inlets.  Multiple “relief” locations distribute air to the various rooms.  In many cases, supply air ducting 

can be eliminated.  The OASys is most easily installed on exterior walls with air supplied through a single 

grille, but ducting may be used to distribute air if guidelines in this manual are followed.  Improper duct 

sizing will cause a reduction of air flow and cooling capacity.

SUPPLY AND INTAKE PLENUMS:  Supply and intake plenums must be sized so that the air ve-

locity of any passage, including grilles, does not exceed 800 feet per minute (maximum velocity = 1766 

divided by the air passage cross sectional area in ft²).

INTAKE AIR DUCTING:  Intake air ducting methods depend on the type of installation.  wall mount 

and exterior mount systems require no ducting.  units mounted in interior spaces or attics require 

ducted intake air.  To facilitate round duct connections, plenum should be at least 16” high.  Do not cut 

openings in the cabinet in any other locations.  

SUPPLY AIR DUCTING:  Size ducting for a maximum pressure drop of 0.25” static pressure.  Mini-

mize the amount of ducting, relying on relief vents for air distribution.  If sharing ducting with a furnace 

and/or refrigerant air conditioner, insure ducts are properly sized and install back draft dampers at both 

OASys and furnace supply plenums.  back draft dampers must be accessible for inspection.

DUCTING SECONDARY AIR:  If necessary to isolate secondary air discharged from the back rear 

of the unit from the intake, a duct connection may be made to the back rear of the unit. Discharging this 

air to the outside is preferable.

AIR RELIEF:  For proper cooling operation, air must be discharged from the house at the same rate 

it is supplied by the OASys.  The preferred method is to vent air into the attic through ceiling-mounted 

grilles with barometric dampers.  by venting air into the attic the attic is kept cooler, reducing ceiling 

heat gain.  Damper assemblies, or “up-Dux”,  are available as accessory equipment.  At least four 12” x 

12” reliefs should be installed per OASys unit.  Air may also be discharged through wall-mounted damp-

ers, operable skylights, or secured windows.