3.2.1.3 FRONT RETURN AIR
Most applications for this style of air-handler bring the return air through into the front
of the unit from the conditioned space with no return duct. The unit is shipped from the
factory to accommodate this type of installation with no modifications. Louvered cabinet
grilles and decorative wall grilles are available as an accessory to facilitate front return
installations. (See Sections 6.4 and 6.5)
3.2.1.4 BOTTOM RETURN AIR
Should the application require the return air to enter the unit from the bottom, the unit
can be easily converted to bottom return using an accessory kit (RXHK series) found in
Section 6.3 of this manual. The conversion involves removing the block-off plate shipped
installed in the bottom of the unit and installing the front door that comes with the con-
version kit. Once converted, the unit can be mounted on a bottom return air platform or
connected to a bottom return duct. If an external filter rack is installed, the unit’s internal
filter must be removed.
3.2.2 R-22 AIR-HANDLER REPLACEMENTS
(-)F1P models can be used to replace an air-handler in applications using R-22 refriger-
ant with a simple orifice (piston) change. Refer to Section 3.8 for recommended orifice
sizes for R-22 systems.
3.2.3 INSTALLATION IN AN UNCONDITIONED SPACE
The exterior cabinet of an air handler has a greater risk of sweating when installed in an
unconditioned space than when it is installed in the conditioned space. This is primarily
due to the temperature of the conditioned air moving through the air handler and the
air circulating around the unit where it is installed. For this reason, the following is rec-
ommended for all air handler applications, but special attention should be paid to those
installed in unconditioned spaces:
• Duct sizing and airflow are critical and must be based on the equipment selected.
• Supply and return duct attachment: If other than the factory flanges are used, the
attachment of ducting must be insulated and tight to prevent sweating.
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FIGURE 4
DIMENSIONS FOR DUCTWORK & DRAINS
