13
NATURAL GAS CONNECTION
Refer to Figure 11 for the general layout at the furnace. The
following rules apply:
1. Use black iron or steel pipe and fittings for the building
piping.
2. Use pipe joint compound on male threads only. Pipe
joint compound must be resistant to the action of the
fuel used.
3. Use ground joint unions.
4. 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.
5. 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 the same as shipped
from the factory.
6. Within six feet of the unit, install a manual cutoff valve
between the meter and the unit. If a union is installed,
the union must be downstream of the manual shutoff
valve, between the shutoff valve and the furnace.
7. Tighten all joints securely.
8. The furnace must be connected to the building piping
by one of the following:
•
Rigid metallic pipe and fittings.
•
Semirigid metallic tubing and metallic fittings. Alumi-
num alloy tubing must not be used in exterior loca-
tions.
•
Listed gas appliance connectors, used in accor-
dance with the terms of their listing, must be com-
pletely in the same room as the furnace.
•
The connectors or semirigid tubing must be pro-
tected against physical and thermal damage when
installed. Aluminum-alloy tubing and connectors must
be coated to protect against external corrosion when
in contact with masonry, plaster or insulation or are
subject to repeated wettings by such liquids as water
(except rain water), detergents or sewage.
Figure 11
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 valve):
• 90 degree elbow
• Close nipple
• 90 degree elbow
• Straight pipe to reach the exterior of the furnace (Fig-
ures 12 & 13).
Figure 12
Gas Inlet Through Furnace Right Side
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.
Figure 13
Gas Inlet Through Furnace Bottom Side
(Upflow)
