Installation Instructions

28
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.
The gas piping may enter the left or right side of the furnace
cabinet. The installer must supply rigid pipe long enough to reach
the outside of the cabinet to seal the grommet cabinet penetra-
tion. A semi-rigid connector to the gas piping can be used out-
side the cabinet per local codes. 1/2” NPT pipe and fittings are
required. For models with an “L” shaped manifold, a 4 1/2”
long nipple is required. For models with a hook shaped mani-
fold, a 2” long nipple is required.
A semi-rigid connector to the gas piping can be used outside
the cabinet per local codes. From the elbow, the length of
pipe and the fittings required will vary by the side chosen,
location of union and cabinet width. The union may be placed
inside or outside of the cabinet.
Alternate
Gas Line
Location
Gas Valve
Burners
Manual Shut Off Valve
(upstream from
ground joint
pipe union)
Drip Leg
Grommet
in Standard
Gas Line
Hole
*Ground
Joint
Pipe
Union
*Ground
Joint
Pipe
Union
*NOTE: Union may be inside furnace cabinet where allowed by local codes.
Manifold
UPFLOW
Figure 34
Gas Connections
T O AVOID THE POSSIBILITY OF EXPLOSION OR FIRE , NEVER USE A MATCH
OR OPEN FLAME TO TEST FOR LEAKS .
WARNING
GAS PIPING CHECKS
Before placing unit in operation, leak test the unit and gas con-
nections.
Check for leaks using an approved chloride-free soap and water
solution, an electronic combustible gas detector, or other ap-
proved testing methods.
NOTE: Never exceed specified pressures for testing. Higher
pressure may damage the gas valve and cause subsequent
overfiring, resulting in heat exchanger failure.
Disconnect this unit and shutoff valve from the gas supply piping
system before pressure testing the supply piping system with
pressures in excess of 1/2 psig (3.48 kPa).
Isolate this unit from the gas supply piping system by closing its
external manual gas shutoff valve before pressure testing supply
piping system with test pressures equal to or less than 1/2 psig
(3.48 kPA).