21
•
Use black iron or steel pipe and fittings for the building
piping.
•
Use pipe joint compound on male threads only. Pipe
joint compound must be resistant to the action of the
fuel used.
•
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.
•
Use two pipe wrenches when making 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.
•
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.
–
Use listed gas appliance connectors in accordance
with their instructions. Connectors must be fully in
the same room as the furnace.
–
Protect connectors and semi-rigid 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.
Gas line
entrance
Right side
gas entrance
(alternate)
General Furnace Layout
U
PFLOW
I
NSTALLATIONS
When the gas piping enters through the right side of the fur-
nace
, the installer must supply the following fittings (starting
from the gas valve):
•
Close nipple.
•
90 degree elbows.
•
Straight pipe to reach the exterior of the furnace .
A ground joint union, drip leg, and manual shutoff valve must
also be supplied by the installer. In some cases, the installer
may also need to supply a transition piece from 1/2" to another
pipe size.
When the gas piping enters through the left side of the furnace,
the installer must supply the following fittings (starting from the
gas valve):
•
90 degree elbow.
•
Straight pipe to reach the exterior of the furnace.
•
A ground joint union, drip leg, and manual shutoff valve
must also be supplied by the installer. In some cases,
the installer may also need to supply a transition piece
from 1/2 inch to another pipe size.
C
OUNTERFLOW
I
NSTALLATIONS
When the gas piping enters through the left side of the furnace,
the installer must supply a straight pipe and a 90 degree elbow
to reach the exterior of the furnace.
A ground joint union, drip leg and manual shutoff valve must
also be supplied by the installer. In most cases, the installer
may also need to supply a transition piece from ½” to another
pipe size. When the gas piping enters through the right side of
the furnace, the installer must supply the following fittings (start-
ing at the gas valve):
•
Close Nipple
•
90 Degree Elbow
•
Straight Pipe to Reach Exterior of Furnace.
