Install Instructions
29
NOTE: Airflow area will be reduced by approximately 18% if duct
flanges are left in factory position. This could cause perfor-
mance issues and noise issues.
Digital
Manometer
Checking Static Pressure
Figure 37
When the furnace is used in connection with a cooling unit, the
furnace should be installed in parallel with or on the upstream
side of the cooling unit to avoid condensation in the heating
element. With a parallel flow arrangement, the dampers or
other means used to control the flow of air must be adequate to
prevent chilled air from entering the furnace and, if manually
operated, must be equipped with means to prevent operation of
either unit unless the damper is in the full heat or cool position.
E
DGES
OF
SHEET
METAL
HOLES
MAY
BE
SHARP
. U
SE
GLOVES
AS
A
PRECAUTION
WHEN
REMOVING
SHEET
METAL
FROM
RETURN
AIR
OPENINGS
.
WARNING
When the furnace is installed without a cooling coil, it is recom-
mended that a removable access panel be provided in the outlet
air duct. This opening shall be accessible when the furnace is
installed and shall be of such a size that the heat exchanger can
be viewed for visual light inspection or such that a sampling
probe can be inserted into the airstream. The access panel
must be made to prevent air leaks when the furnace is in opera-
tion.
When the furnace is heating, the temperature of the return air
entering the furnace must be between 55°F and 100°F.
FILTERS - READ THIS SECTION BEFORE INSTALLING THE RETURN
AIR DUCT
CUT USING TIN SNIPS
SCRIBE LINES OUTLINING
DUCT FLANGES
Dual Flange Cut Outs
Figure 38
Filters must be used with this furnace. Discuss filter mainte-
nance with the building owner. Filters do not ship with this fur-
nace, but must be provided, sized and installed externally by the
installer. Filters must comply with UL900 or CAN/ULCS111 stan-
dards. Damage or repairs due to the installation of the fur-
nace without filters is not covered under the warranty.
On upflow units, guide dimples locate the side return cutout lo-
cations. Use a straight edge to scribe lines connecting the dimples.
Cut out the opening on these lines.
NOTE: An undersized opening will cause reduced airflow.
HORIZONTAL INSTALLATIONS
Filters must be installed in either the central return register
or in the return air duct work.
UPRIGHT INSTALLATIONS
Depending on the installation and/or customer preference, dif-
fering filter arrangements can be applied. Filters can be in-
stalled in the central return register or a side panel external filter
rack kit (upflows). As an alternative a media air filter or elec-
tronic air cleaner can be used as the requested filter. Consider
installing an air cleaner with deep-pleated media filter at
the time of furnace installation. A deep-pleated filter with a
MERV rating of 8 (minimum) will often provide better filtra-
tion to protect equipment and the air distribution system
than a standard 1" filter and often has lower static pressure
loss than a 1" filter. Also a deep-pleated filter will typically
require less frequent replacement intervals. Avoid using
highly restrictive 1" filters which produce static pressure
loss greater than .25" W.C. In some installations the mini-
mum filter size required will not lend itself to a filter instal-
lation on the side of the furnace. The installation of a cen-
trally installed air cleaner cabinet or a return duct filter in-
stallation may offer more practicality.