MG3P Installation Manual

18
4. Position the A/C coil box on the top of the furnace and secure
in place using the provided attachment brackets. To install
the brackets: position one bracket on side of furnace and
using the provided self-drilling screws, secure the bracket
to the A/C coil box and the furnace. Repeat for other side of
furnace.
5. Position the plenum on top of the coil box and secure together
with sheet metal screws. The screws must penetrate the sheet
metal casing and coil box flange.
6. Secure the supply air ductwork to the plenum. Tape or seal
all seams if required by local code.
Bottom Panel Removal
The steps listed below describe how to remove the bottom panel
from the furnace. Figure 22.
1. Remove the door from the blower compartment.
2. Disconnect the blower motor wires from the blower motor
plug.
3. Remove two screws securing the blower assembly to the
furnace.
4. Carefully pull the blower assembly out thru the front of the
furnace.
5. Remove all screws securing bottom panel to bottom of furnace
and front brace.
6. Lift up and slide bottom panel out through front of
furnace.
7. Reinstall the blower assembly in reverse order.
Alternate Bottom Panel Removal
If the bottom panel cannot be removed using the previous
instructions, the steps below are an alternate method for removing
the bottom panel. See Figure 23 (page 18).
1. Remove the door from the blower compartment .
2. Remove all screws securing the bottom panel to the front
brace.
3. Remove two screws securing the furnace cabinet to the blower
deck.
4. Remove all screws securing the furnace cabinet to the bottom
panel.
5. Remove the screw securing the bottom corner of the furnace
cabinet to the front brace.
6. Carefully spread the bottom corner of the furnace cabinet
outwards while sliding the bottom panel out through the front
of the furnace.
7. Reassemble the furnace in reverse order.
Inducer & Venting Options
To increase installation flexibility, the inducer assembly can be
rotated up to 3 different positions. Each variation has slightly
different requirements with regard to condensate disposal and,
in some cases, the need to seal the furnace cabinet.
1. Prior to vent installation, determine the number of pipes to
be connected to the furnace (1-pipe or 2-pipe), the airflow of
the furnace (upflow or downflow), and then the side that the
pipes will exit from the furnace.
2. Select the option from Table 4 that properly matches your
installation type and then find your setup (by Option number)
in Figure 53 (page 52) & Figure 54 (page 53).
IMPORTANT NOTE: The inducer assembly must never be
positioned to vent downwards.
It is important that Direct Vent (2-pipe) systems maintain an
airtight flow path from the air inlet to the flue gas outlet. The
furnace ships from the factory with two holes in the cabinet for
the air inlet and flue gas outlet. In certain configurations, it is
necessary to remove and relocate a plastic cap in the furnace
cabinet. If changing the position of the air inlet and flue gas outlet,
it is required that the previous hole be closed off with the plastic
Bottom
Panel
Front
Brace
Door
Blower
Plug
Screws
Blower
Assembly
Screws
Figure 22. Bottom Panel Removal
Figure 23. Alternate Removal Method
Screws
Front
Brace
Bottom
Panel
Screws
Blower
Deck
Door
1 PIPE INSTALLATIONS
VENT UPFLOW (MG3P) DOWNFLOW (MG3S)
Up Option 1 Option 8
Right Option 2 Option 7
Left Option 3 Option 9
2-PIPE INSTALLATIONS
VENT UPFLOW (MG3P) DOWNFLOW (MG3S)
Up Option 4 Option 11
Right Option 5 Option 10
Left Option 6 Option 12
Table 4. Vent & Inducer Blower Options