Bottom Return Air Opening - Intertek MVM97 Series Installation Instructions Manual

B R A O
OTTOM ETURN IR PENING
The bottom return air opening on upflow models utilizes a "lance and cut" method to remove sheet metal from the duct opening in the
base pan. To remove, simply press out the lanced sections by hand to expose the metal strips retaining the sheet metal over the duct
opening. Using tin snips, cut the metal strips and remove the sheet metal covering the duct opening. In the corners of the opening,
cut the sheet metal along the scribe lines to free the duct flanges.
Using the scribe line along the duct flange as a guide, bend the
duct flanges around the perimeter of the opening using a pair of
seamer pliers or seamer tongs.
NOTE: Airflow area will be reduced by approximately 18% if duct
flanges are not folded open. This could cause performance is-
sues and noise issues.
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.
When the furnace is installed without a cooling coil, it is recommended
that a removable access panel be provided in the supply air plenum.
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 air-
stream. The access panel must be sealed 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 .
F - R T S
ILTERS EAD HIS ECTION
WORK
Filters must be used with this furnace. Discuss filter maintenance 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. If the furnace is installed without filters, the war-
ranty will be voided.
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 undersized opening will cause reduced airflow.
Refer to the Filter Sizing Chart to determine filter area requirements.
Change filters before occupants take ownership of a new home!
[U M ]
PFLOW ODELS
B I T R
EFORE NSTALLING HE ETURN
E
DGES OF SHEET METAL HOLES MAY BE SHARP
PRECAUTION WHEN REMOVING SHEET METAL FROM RETURN AIR
.
OPENINGS
CUT USING TIN SNIPS
CUT FOUR CORNERS
AFTER REMOVING SHEET
METAL
A D
IR UCT
*MVM970603BN**
*MVM970803BN**
*MVM970804CN**
*MVM971005CN**
*MVM971205DN**
*CVM970603BN**
*CVM970803BN**
*CVM970804CN**
*CVM971005CN**
[Based on 300 ft/min filter face velocity]
WARNING
. U
SE GLOVES AS A
PRESS OUT BY HAND
SCRIBE LINES OUTLINING
DUCT FLANGES
Duct Flange Cut Outs
Figure 41
Filter Sizing Chart
Model Minimum Filter Size
24 X 30
24 X 30
24 X 36
24 X 36
(2) 20 X 25
20 X 25
24 X 30
24 X 30
24 X 36
37