American Standard S9X1 Installer's Manual page 21

Important: When converting the gas piping from the factory default,
the plug must be removed from the new gas piping
location and swapped with the grommet from the default
location. The upflow furnace default is left side gas
piping. The downflow furnace default is right side gas
piping.
Horizontal left furnace with gas piping out left side
Automatic Gas Valve
with Manual Shut-o
1/8" NPT Ground
Test Fitting Union
Joint
Main Manual
Shut-o Valve
Horizontal right furnace with gas piping out left side
Gas Line
Grommet
18-CE12D1-1D-EN
Gas Line
Grommet
Drip Leg
Main Manual
Shut-o Valve
Ground
1/8" NPT
Union
Test Fitting
Joint
Drip Leg
Automatic Gas
Valve with
Manual Shut-o
F F u u r r n n a a c c e e G G e e n n e e r r a a l l I I n n s s t t a a l l l l a a t t i i o o n n
Horizontal left furnace with gas piping out right side
Ground
1/8" NPT
Union
Test Fitting
Joint
Drip Leg
Main Manual
Shut-o Valve
Automatic Gas Valve
with Manual Shut-o
Horizontal right furnace with gas piping out right side
Gas Line
Grommet
Gas Line
Grommet
Automatic Gas Valve
with Manual Shut-o
Ground
Main Manual
Union
Shut-o Valve
Joint
1/8" NPT
Test Fitting
Drip Leg
21