GM9S96 Service Manual
SYSTEM OPERATION
17
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cy by extracting almost all of the heat from the products of
combustion and cooling them to the point where condensa-
tion takes place. The condensate which is generated must
be piped to an appropriate drain location.
WARNING
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• If the drain line is routed through an area which may
see temperatures near or below freezing, precautions
must be taken to prevent condensate from freezing
within the drain line.
• If an air conditioning coil is installed with the furnace,
a common drain may be used. An open tee must
be installed in the drain line, near the cooling coil, to
relieve positive air pressure from the coil’s plenum.
This is necessary to prohibit any interference with the
function of the furnace’s drain trap.
Horizontal installations require 5.5” under the fur-
nace to accommodate the drain trap. The horizontal furnace
must be installed with ¾” slope from back to front to permit
When installing a *M9S9* horizontally with the left side
down, there are two options for connecting the vent pipe to
the furnace.
Option 1
the original top (now the end) of the furnace.
Option 2
The internal vent pipe and elbow may be removed from the
furnace to permit the vent to exit the top (original side) of
the furnace. If this option is used, an RF000142 Vent-Drain
coupling must be used to keep condensate from collecting
in the inducer assembly.
To install the drain, refer to the following instructions and
illustration.
COMBUSTION AIR INTAKE PIPE OPTIONS:
The RF000142 coupling can be secured directly to the
furnace intake coupling if condensation is occurring in the
combustion air inlet pipe. If the RF000142 is used on the
combustion air inlet, it must be installed with the arrow
pointing up. It should be noted, the combustion air will
actually be moving in a direction opposite of the arrow on the
RF000142 coupling.
Alternatively a tee may be used in the combustion air in-
take pipe for the same purpose. If either option is used, a
condensate disposal location must be present. A loop in the
drain tube can serve as a trap. The unused RF000142 drain
1.
2. Remove internal elbow and vent pipe.
3.
4. Remove cabinet plug adjacent to inducer outlet and
install an original cabinet vent hole.
5. Install RF000142 coupling on inducer outlet.
6. -
cure with clamps.
7.
step 1.
Insert flange. Cut 2 ½” long.
R 000142F