FOR HVAC INSTALLER ONLY
Ultra-Aire 90H Installer’s & Owner’s Manual
4.4C Installation in a Basement or Crawlspace with an
Existing Forced Air HVAC System.
Basement Installation:
Install a separate 10" return for the UA-90H
in a central area of the structure. Optional: Duct the supply of the
Ultra-Aire to a 10" x 10" x 10" tee/damper, adjusted to 20% open
to the basement. Duct the other side of the tee to the air supply of
the existing HVAC system with a backdraft damper. Connect a duct
from outside to the 6" collar of the Ultra-Aire if you wish to provide
ventilation air. See Figure 2.
Crawlspace Installation:
Install a separate return for the UA-90H
in a central area of the structure. Optional: Duct the supply of the
UA-90H to a 10" x 10" x 10" tee/damper that is 20% open to the
crawlspace if desired. Duct the other side of the tee to the air supply
of the existing HVAC system with a backdraft damper.
Connect an insulated duct from outside to the 6" collar of the UA-
90H if you wish to provide optional ventilation air.
Instead of installing a separate return to the UA-90H, and if the
existing system has multiple returns, it is possible to select one to
disconnect from the existing forced air system and use it for the
dedicated Ultra-Aire return. Always select a return from a central
location in the structure in an area that is always open to the rest
of the structure. Do not use a return from a room that may have
its door closed much of the time or, alternatively, install a separate
return from the open part of the house.
4.4D Installation in an Attic with an Existing Forced Air
HVAC System
CAUTION!
ALWAYS install a catch pan with a drain or float interrupt for
condensate under the UA-90H in an attic or condensate may
damage the living space below.
The interrupt switch should be installed in series with the field
wire that connects the blue (#5) lead from the UA-90H to the
blue (#5) lead on the control panel. If overflow occurs, this switch
opens the compressor control circuit and stops water production
before the catch pan overflows. The UA-90H will continue to
ventilate or circulate air as normal, but will not dehumidify until
this switch closes.
The preferred method of installation is to create a separate return for
the UA-90H in a central area of the structure. Duct the supply of the
UA-90H to the air supply of the existing HVAC system. Connect an
insulated duct from outside to the 6" collar of the UA-90H if you wish
to provide fresh make-up air. Adjust a damper in the duct to provide
the desired.
4.4E Installation in a Structure with No Existing Forced
Air HVAC System
When installing the UA-90H in a structure that does not have a
forced air HVAC system, a single return for the UA-90H should be
installed in central open area of the structure. DO NOT locate the
return in a bathroom or a kitchen. The supplies of the UA-90H should
be located in the remote areas of the structure (such as bedrooms,
den, etc.). By ducting this way, the air inside the structure will
circulate through the UA-90H to be filtered and dehumidified. 6"
diameter duct is recommended for branches to the bedrooms, 8"
diameter duct is recommended for branches to larger areas. Connect
an insulated duct from outside to the 6" collar of the UA-90H if you
wish to provide ventilation. See Figure 4.
8
