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Ultra-Aire 98H Installation Instructions
Fresh air ventilation is optional.
Fresh air may be brought into the structure by connecting an insulated duct from outside the structure to
the 6" inlet of the Ultra-Aire 98H. A ventilation control is needed to program the time and frequency that
the unit introduces outside air. The time and frequency of ventilation should be based on the size and
occupancy of the residence.
• The fresh air ventilation duct should be connected to the 6" round collar on the front of the Ultra-Aire 98H.
• An insulated 6" diameter duct provides up to 75 CFM of outside air.
• If a motorized damper is not being used, fresh air is controlled by the manual damper in the 6” collar of the
Ultra-Aire 98H.
• Performance of the Ultra-Aire 98H can be impacted by inside and outside air conditions.
• When a 6" motorized damper is used, a digital control is required.
• It may be necessary to use 8" duct work if additional fresh air is required.
• In cold climates or at times when the dew point is low, ventilation can be used to dehumidify the
structure, making the Ultra-Aire 98H capable of year-round drying.
FRESH AIR VENTILATION
OUTLET DUCT
COLLAR WITH
BACK DRAFT
DAMPER
RETURN AIR
INLET DUCT
COLLAR
FRESH AIR
INLET DUCT
COLLAR
RETURN AIR
INLET DUCT
COLLAR
FRESH AIR
INLET DUCT
COLLAR
AIR FLOW
Air
Flow
Outdoor Air
90°F, 65%RH
Indoor Air
70°F, 50%RH
Mixed Air
75°F
65%RH
Mixed Air
75°F
65%RH
Outlet Air
75°F, 65%RH
Hot Climate
6" Fresh Air Inlet
(Optional)
10" Return Air Inlet
10" Supply Air Outlet
A
B
C
A
B
C
Outdoor Air
30°F, 65%RH
Indoor Air
70°F, 50%RH
Outlet Air
59°F, 51%RH
Cold Climate
A
B
C
6" Fresh Air Inlet
(Optional)
10" Return Air Inlet
10" Supply Air Outlet
A
B
C
Mixed Air
59°F
51%RH
Mixed Air
59°F
51%RH
Fresh Air Ventilation With Dehumidifier Off and Fan Only Operation
Outside air mixes with the dehumidifier’s return air before being supplied to the home. Outside
temperature, inside temperature and relative humidity will impact the combined outlet air conditions.
Note: Temperature and relative humidity may vary depending on duct distribution scheme.
