32
The following stipulations apply when connecting gas piping. Re-
fer to
Gas Piping Connections
figure for typical gas line connec-
tions to the furnace.
•
Gas piping must be supported external to the furnace
cabinet so that the weight of the gas line does not distort
the burner rack, manifold or gas valve.
•
Use black iron or steel pipe and fittings for building piping.
Where possible, use new pipe that is properly chamfered,
reamed, and free of burrs and chips. If old pipe is used, be
sure it is clean and free of rust, scale, burrs, chips, and old
pipe joint compound.
•
Use pipe joint compound on male threads ONLY. Always
use pipe joint compound (pipe dope) that is APPROVED
FOR ALL GASSES. DO NOT apply compound to the first
two threads.
•
Use ground joint unions.
•
Install a drip leg to trap dirt and moisture before it can enter
the gas valve. The drip leg must be a minimum of three
inches long.
•
Install a 1/8" NPT pipe plug fitting, accessible for test gage
connection, immediately upstream of the gas supply
connection to the furnace.
•
Always use a back-up wrench when making the connection
to the gas valve to keep it from turning. The orientation of
the gas valve on the manifold must be maintained as shipped
from the factory. Maximum torque for the gas valve
connection is 375 in-lbs; excessive over-tightening may
damage the gas valve.
•
Install a manual shutoff valve between the gas meter and
unit within six feet of the unit. 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:
–
Rigid metallic pipe and fittings.
–
Semi-rigid metallic tubing and metallic fittings.
Aluminum alloy tubing must not be used in exterior
locations. In order to seal the grommet cabinet
penetration, rigid pipe must be used to reach the outside
of the cabinet. A semi-rigid connector to the gas piping
may be used from there.
•
Use listed gas appliance connectors in accordance with
their instructions. Connectors must be fully in the same
room as the furnace.
•
Protect connectors and semirigid tubing against physical
and thermal damage when installed. Ensure aluminum-
alloy tubing and connectors are coated to protect against
external corrosion when in contact with masonry, plaster,
or insulation, or subjected to repeated wetting by liquids
such as water (except rain water), detergents, or sewage.
MANUAL
SHUT OFF VALVE
(UPSTREAM FROM
PIPE UNION)
GROMMET
IN STANDARD
GAS LINE HOLE
GAS LINE
PLUG IN
GAS LINE
HOLE
HEIGHT REQUIRED
BY LOCAL CODE
PIPE UNION
DRIP LEG
MANIFOLD
BURNERS
GAS VALVE
PLUG IN
ALTER NATE
GAS LINE
HOLE
DRIP LEG
BURNERS
GAS VALVE
