MG3P Installation Manual

17
Installing the Downflow Furnace
1. Prepare the AC coil box for installation by removing 2 screws
from the sides of the A/C coil box.
2. Install the close-off plate on the bottom of the of the coil box.
See Figure 19.
3. Align the screw holes in the close off plate and the coil box.
Secure both components with the screws removed in step 1.
4. Place the A/C coil box on the duct connector until the back
side butts firmly against the mounting plate tabs. NOTE:
Mounting plate tabs must be bent upwards as shown in Figure
14 (page 16) to prevent interference with furnace.
5. Secure the A/C coil box to the connector assembly and wood
floor with appropriate size screws at all four corners. NOTE:
To minimize coil box damage, see Figure 20 for appropriate
screw locations.
6. Install the furnace on top of the A/C coil box. Align the furnace
evenly on the coil box from front to back and side to side.
7. Secure the furnace to the A/C coil box with an attachment
bracket on both sides of the furnace. NOTE: The attachment
brackets must be evenly positioned over the seam between
the A/C coil box and the furnace. Install 4 self drilling screws
in each bracket. See Figure 21.
Figure 21. Attachment Bracket
Attachment
Bracket
Furnace
A/C Coil Box
Figure 19. Close-Off Plate
Mounting
Plate
Screw Down
Duct Connector
Supply
Air Duct
Hole for
Gas Line
Wood Floor
Bend tabs
up 90°
Figure 18. Screw-Down Duct Connector
Figure 20. A/C Coil Box Installation
DO NOT INSTALL SCREWS
IN THIS SURFACE
Coil Box
Supply
Air Duct
2 Screws
both sides
Wood
Floor
Upflow Furnace Installation
WARNING:
The furnace must not be installed directly on
carpeting, tile, or any combustible material other
than wood flooring.
The MG3P series gas furnace is certified for use on wood flooring
or supports. The upflow furnace is shipped with the bottom panel
(Figure 44 (page 36)) installed and must be removed from
the bottom of the cabinet before positioning and installing the
furnace. See Bottom Removal section for removal instructions.
NOTE: These Installation procedures are suggested for typical
furnace installations. Since all installations are different from
each other, the sequence of these steps may differ from the
actual installation.
1. Position the furnace on top of the return air ductwork or return
air stand ensuring even alignment of furnace air opening and
return air duct. NOTE: The ductwork or stand must have an
opening equal to that of the return air opening of the furnace.
See the cabinet dimensions in Figure 44 for the proper return
air opening size.
2. Secure the furnace to the floor or base. Check for level from
front to back and side to side. NOTE: Additional fasteners
may be used at rear, sides or through door frame, as desired,
to secure furnace to closet or alcove framing.
3. Secure the return air ductwork to the bottom of the furnace
with self drilling screws.