All installations and services must be performed by qualified service personnel.
These furnaces may be installed in an alcove or in a closet if the minimum clearances to combustible
construction (listed previously) are met. The CDX3 series furnaces may be installed in an attic or crawl
space. Refer to section III, B1 of this installation manual.
The minimum clearances are listed for fire protection. Clearance for servicing the front of the furnaces
and to all points on the furnace requiring access must be 24”*.
*For horizontal furnace installation, refer to section III, B1 of this installation manual.
Equipment must be installed in accordance with regulations of the National Board of Fire
Underwriters. Authorities having jurisdiction should be consulted before installations are made.
B. FURNACE
LOCATION
: These high efficiency condensing furnaces are not certified for and shall not be
vented into a standard or any type of chimney.
The following shall be considered for locating the furnace:
1. For best performance locate the furnace so that it is centralized with respect to the duct system and
as near as possible to a floor drain since condensate drainage must be provided.
2. Place the unit so that proper venting can be achieved, with a minimum number of elbows, in accord
with the instructions in this manual.
3. The furnace must be located on a level, dry surface. The furnace must be installed so that the
electrical components are protected from water. If the area becomes wet or damp at times, the
furnace should be raised above the floor using a concrete base, bricks, patio blocks, etc.
NOTICE: Ensure furnace is level after installation to ensure proper drainage and operation.
4. This furnace must be connected to a drain in accordance with these instructions. If it is not practical
to connect the unit to a drain, a condensate pump must be used and can be ordered as an
accessory, part number 350225. If an acid neutralizer kit is required by local code or the customer, it
is available under part number 320095.
B1. CDX3 HORIZONTAL APPLICATION
The CDX3-75, 100, and 125 furnaces may be installed in a horizontal position by placing the furnace on
the left or right side (as viewed from the front in the upright position).
For left or right horizontal applications of the CDX3 series units, the rollout switch located on the burner
box must be moved to the pre-punched mounting holes on the side of the burner box. Screws are
provided in pre-punched holes at the required limit location. Remove these screws and use them to
mount the limit to new location. Utilize previously removed limit mounting screws to fill voided holes at
previous limit location (See Figure 1).
For a right side horizontal application of the CDX3 series units, the hose from the single tap pressure
switch (top switch) is already connected correctly (See Figure 1).
For a left side horizontal application of the CDX3 series units, the hose from the single tap pressure
switch (bottom switch) must be moved to the lower front tap on the face of the collector box. Use the
black cap removed from this tap to plug the original pressure switch tap.
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