MG3P Installation Manual

20
Accessories
The components in Figure 27, Figure 28 (page 20), Figure 29,
& Figure 30 are included in the extra parts bag that is supplied
with the purchase of MG3(P,S) furnaces. Depending on your
particular installation, some of these components are optional
and may not be used. Please refer to the descriptions and
accompanying figures when installing these items.
Finish Flange
The finish flange must be installed to vent the combustion air
pipe through the top of the furnace. See Figure 27.
NOTE: For proper installation, it is important that the pipe and
screw holes in the finish flange, gasket, and cabinet are aligned.
1. Position flange gasket and finish flange on top of the furnace
cabinet. Evenly align vent hole and screw holes in gasket,
flange, and cabinet.
2. Position finish flange on top of the flange gasket with the
FRONT lettering nearest to the front of the furnace.
3. Secure flange and gasket to cabinet with three field supplied
sheet metal screws.
Rubber Grommets
The 2 1/4” rubber grommet is used to seal the opening between
the furnace cabinet and the 2” PVC vent pipe. The rubber grommet
should be installed in one of the 3” holes prior to running the vent
pipe out of cabinet. No sealants are required. See Figure 28.
The 7/8” rubber grommet is used to seal the opening between the
furnace cabinet and the gas pipe. The rubber grommet should
be installed in the 1 5/8” hole prior to running the gas pipe into
the cabinet. No sealants are required.
The 3/4” rubber grommet is used if venting out the left side of
the cabinet and the drain tube is routed through the blower deck.
Remove the plastic plug from the hole and install the grommet
before routing the drain tube.
Inline Drain Assembly
1. If applicable, install the inline drain assembly on the inducer
assembly. See Figure 29.
2. Insert the vent pipe through the hole in the cabinet and into
the inline drain assembly.
3. Verify the vent pipe, inline drain assembly, and inducer are
aligned properly for drainage of condensate.
4. Tighten both clamps to secure the inline drain assembly.
5. Insert smaller end of the 3/8” x 1/2” hose barb into the lowest
port of the inline drain assembly. Connect the condensate
drain tube to the hose barb and cap off the other port.
Finish Flange
Flange Gasket
Hole for Flue
Vent Pipe
Hole for Inlet
Air Vent Pipe
FRONT
FRONT lettering must be
located near front
of furnace
Figure 27. Finish Flanges
Figure 28. Rubber Grommets
ø 2 1/4” Rubber
Grommet
ø 7/8” Rubber
Grommet
ø 3/4” Rubber
Grommet
PVC Components
IMPORTANT NOTES:
• Before permanently installing these components, it is
recommended you dry-fit them first to ensure proper fit
and alignment with other vent pipes.
• The PVC components shown in Figure 30 are not provided
in the extra parts bag. However the PVC Trap (P/N 664659)
can be purchased thru your local distrubtor.
The PVC tee with PVC Trap or the reducer and 1/2” X 1/2” hose
barb are used when the inducer is rotated to vent out thru the left
or right side of the furnace cabinet. See Figure 30 (page 21).
NOTE: If supplied with your furnace, PVC trap (P/N 664659)
may be used in place of the reducer and 1/2” X 1/2” hose barb
The 1/2” x 3/4” hose barb can be used to route the
condensate drain to the outside of the cabinet. It must
be installed from inside the cabinet with the threaded
end inserted thru the 1 1/16” hole. The Condensate drain
should be connected to the barbed end. Attach 1” PVC
drain line to the threaded end.
Typical Orientation
1. Install the PVC Tee vertically on the 2” vent pipe that is
extending out the side of the cabinet. Permanently bond them
together using appropriate primer and cement. Refer to the
typical orientation shown in Figure 30.
VENT GASSES
Condensate Drain
Tube
Inducer
Inline Drain
Assembly
Cap
Clamps
Vent Pipe
3/8” x 1/2” Hose Barb
Figure 29. Inline Drain Assembly