SYSTEM OPERATION
42
.
Checking Static Pressure
Figure 42
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 condensa tion in
the heating element. With a parallel flow arrange ment, 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 rec
-
ommended 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 operation.
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 WORK
CUT FOUR CORNERS
AFTER REMOVING SHEET
METAL
CUT USING TIN SNIPS
PRESS OUT BY HAND
SCRIBE LINES OUTLINING
DUCT FLANGES
Duct Flange Cut Outs
Figure 43
Filters must be used with this furnace. Discuss filter mainte
-
nance with the building owner. Filters do not ship with this
furnace, but must be provided, sized and installed externally
by the installer. Filters must comply with UL900 or CAN/
ULCS111 standards. Damage or repairs due to the installation
of the furnace without filters is not covered under the warranty.
On upflow units, guide dimples locate the side return cutout
locations. Use a straight edge to scribe lines connecting the
dimples. Cut out the opening on these lines.
NOTE:
An un
-
dersized opening will cause reduced airflow.
UPRIGHT INSTALLATIONS
Depending on the installation and/or customer preference,
differing filter arrangements can be applied. Filters can be
installed in the central return register or a side panel external
filter rack kit (upflows). As an alternative a media air filter or
electronic 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
filtration 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 minimum
filter size required will not lend itself to a filter installation on
the side of the furnace. The installation of a centrally installed
air cleaner cabinet or a return duct filter installation may offer
more practicality.
Clean Comfort™ brand MERV 11 air cleaners have 5¼”
media filters and are available in the following configurations.
Consult your distributor for information on our complete line
of IAQ Clean Comfort™ products.