18
■
Always use pipe joint compound (pipe dope) that is approved
for all gases.
NOTE: Do not apply compound to the first 2 threads.
■
Use ground joint unions.
■
Install a drip leg to trap dirt and moisture before it can enter
the gas control valve.
NOTE: The drip leg must be a minimum of 3" (7.6 cm) long.
■
Install a
¹⁄₈
" NPT pipe plug fitting, accessible for test gage
connection, immediately upstream of the gas supply
connection to the furnace.
■
Use 2 pipe wrenches when making the connection to the gas
control valve to keep it from turning.
NOTE: The orientation of the gas control valve on the
manifold must be maintained as shipped from the factory.
■
Install a manual shutoff valve between the gas meter and the
furnace within 6 ft (1.8 m) of the furnace.
■
If a union is installed, the union must be downstream of the
manual shutoff valve, between the shutoff valve and the
furnace.
■
Tighten all joints securely.
■
Connect the furnace to the building piping by one of the
following methods:
1. Rigid metallic pipe and fittings.
2. Semirigid metallic tubing and metallic fittings.
NOTE: Aluminum alloy tubing must not be used in exterior
locations.
■
Use UL Listed gas appliance connectors in accordance with
their instructions.
■
Gas connectors must be fully in the same room as the
furnace.
■
Protect gas connectors and semirigid tubing against physical
and thermal damage when installed.
■
Ensure that aluminum alloy tubing and connectors are coated
to protect against external corrosion when in contact with
masonry, plaster, insulation or subjected to repeated wetting
by liquids such as water (except rain water), detergents or
sewage.
General Furnace Layout
Upflow Installations
When the gas piping enters through the right side of the furnace,
the installer must supply the following fittings (starting from the
gas control valve):
■
90º elbows (2)
■
Close nipple
■
Straight pipe to reach the exterior of the furnace
■
Ground joint union
■
Drip leg
■
Manual shutoff valve
■
Transition piece from
¹⁄₂
" to another pipe size, if needed
When the gas piping enters through the left side of the furnace,
the installer must supply the following fittings (starting from the
gas control valve):
■
Straight pipe to reach the exterior of the furnace
■
Ground joint union
■
Drip leg
■
Manual shutoff valve
■
Transition piece from
¹⁄₂
" to another pipe size, if needed
Counterflow Installations
When the gas piping enters through the left side of the furnace,
the installer must supply a straight pipe to reach the exterior of
the furnace.
When the gas piping enters through the left side of the furnace,
the installer must supply the following fittings (starting from the
gas control valve):
■
Straight pipe to reach the exterior of the furnace
■
Ground joint union
■
Drip leg
■
Manual shutoff valve
■
Transition piece from
¹⁄₂
" to another pipe size, if needed
When the gas piping enters through the right side of the furnace,
the installer must supply the following fittings (starting from the
gas control valve):
■
90º elbows (2)
■
Close nipple
■
Straight pipe to reach the exterior of the furnace
Gas Piping Checks
Before placing the unit in operation, leak test the unit and gas
connections.
Check for leaks using an approved chloride-free soap and water
solution, an electronic combustible gas detector or other
approved testing methods.
A. Manual shutoff valve location
(upstream of ground joint pipe union)
B. Height required by local codes
C. Ground joint pipe union (upstream of
gas control valve)
D. Drip leg
E. Reducing coupling—
¹⁄₂
" x
¹⁄₈
"
with
¹⁄₈
" pipe plug to
measure line gas pressure
‘‘
A
B
C
D
E
Goodman 63
To avoid the possibility of explosion or fire, never use a
match or open flame to test for leaks.
WARNING
Goodman 72
To prevent property damage or personal injury due to
fire, the following instructions must be performed
regarding gas connections, pressure testing, location
of shutoff valve and installation of gas piping.
WARNING
