Installation Guide

7
• If the furnace is installed horizontally, ensure the access
doors are not on the “up/top” or “down/bottom” side
of the furnace.
• Do not connect this furnace to a chimney flue that
serves a separate appliance designed to burn solid
fuel.
• On Counterflow Installations, the air conditioning
coil must be downstream on the supply (positive)
side of the furnace heat exchanger.
• Counterflow Installation over a noncombustible
floor. Before setting the furnace over the plenum
opening, ensure the surface around the opening is
smooth and level. A tight seal should be made
between the furnace base and floor by using a
silicone rubber caulking compound or cement grout.
• Counterflow Installation over a combustible floor. If
installation over a combustible floor becomes necessary,
use an accessory subbase (see Specification Sheet
applicable for your model for details.) A special accessory
subbase must be used for upright counterflow unit
installations over any combustible material including
wood. Refer to subbase instructions for installation
details. Follow the instructions with the subbase for
proper installation. Do not install the furnace directly
on carpeting, tile, or other combustible material other
than wood flooring. (NOTE: The subbase will not be
required if an air conditioning coil is installed between
the supply air opening on the furnace and the floor.)
CLEARANCES AND ACCESSIBILITY
POSITION* SIDES REAR FRONT BOTTOM FLUE TOP
Upflow 0" 0" 3" C 0" 1"
Horizontal 6" 0" 3" C 0" 6"
C = If placed on combustible floor, floor MUST be wood only.
*MVC96* MINIMUM CLEARANCES TO COMBUSTIBLE MATERIALS
(INCHES)
NOTES:
• For servicing or cleaning, a 24” front clearance is required.
• Unit connections (electrical, flue and drain) may necessitate
greater clearances than the minimum clearances listed above.
• In all cases, accessibility clearance must take precedence
over clearances from the enclosure where accessibility
clearances are greater.
POSITION* SIDES REAR FRONT BOTTOM FLUE TOP
Counterflow0"0"3"NC0"1"
Horizontal 6" 0" 3" C 0" 6"
C = If placed on combustible floor, floor MUST be wood only.
NC = For installation on non-combustible floors only. A combustible subbase
must
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*CVC96* MINIMUM CLEARANCES TO COMBUSTIBLE MATERIALS
(INCHES)
NOTES:
• For servicing or cleaning, a 24” front clearance is required.
• Unit connections (electrical, flue and drain) may necessitate
greater clearances than the minimum clearances listed above.
• In all cases, accessibility clearance must take precedence
over clearances from the enclosure where accessibility
clearances are greater.
Installations must adhere to the clearances to combustible mate-
rials to which this furnace has been design certified. The mini-
mum clearance information for this furnace is provided on the
unit’s clearance label. These clearances must be permanently
maintained. Clearances must also accommodate an installation’s
gas, electrical, and drain trap and drain line connections. If the
alternate combustion air intake or vent/flue connections are used
additional clearance must be provided to accommodate these
connections. Refer to Vent/Flue Pipe and Combustion Air Pipe
for details.
NOTE: In addition to the required clearances to combustible
materials, a minimum of 24 inches service clearance must be
available in front of the unit.
TOP
BOTTOM
SIDE SIDE SIDE
TOP
BOTTOM
Upflow Counterflow Horizontal
Figure 1
A furnace installed in a confined space (i.e., a closet or utility
room) must have two ventilation openings with a total minimum
free area of 0.25 square inches per 1,000 BTU/hr of furnace
input rating. Refer to Specification Sheet applicable to your model
for minimum clearances to combustible surfaces. One of the
ventilation openings must be within 12 inches of the top; the
other opening must be within 12 inches of the bottom of the
confined space. In a typical construction, the clearance between
the door and door frame is usually adequate to satisfy this ven-
tilation requirement.
EXISTING FURNACE REMOVAL
NOTE: When an existing furnace is removed from a venting
system serving other appliances, the venting system may be too
large to properly vent the remaining attached appliances.
The following vent testing procedure is reproduced from the
American National Standard/National Standard of Canada for
Gas-Fired Central Furnaces ANSI Z21.47, CSA-2.3 latest edition
Section 1.23.1.
The following steps shall be followed with each appliance con-
nected to the venting system placed in operation, while any other
appliances connected to the venting system are not in operation: