506305-01
Page 23 of 36
Issue 0938
Gas supply piping should be installed in accordance with local
codes and the regulations of the utility. Piping must be of
adequate size to prevent undue pressure drop. Consult the
local utility or gas supplier for complete details on special
requirements for sizing gas piping.
If local codes allow the use of a flexible gas appliance
connector, always use a new listed connector. Do not use a
connector which has previously serviced another gas
appliance.
Pipe connections must be tight, and a non-hardening pipe
compound resistant to liquefied petroleum gases should be
used.
Connect the gas pipe to the furnace controls providing a
ground joint union as close to the controls as is possible to
facilitate removal of controls and manifold. Provide a drip
leg on the outside of the furnace. A manual shutoff valve
shall be installed in the gas line, outside the unit, 5' above
the floor, or in accordance with any local codes. A test
gauge connection must be installed with a 1/8" NPT plugged
tapping immediately upstream of the shutoff valve (see
Figure 35).
The furnace must be isolated from the gas supply piping
system by closing the individual manual shutoff valve during
any pressure testing of the gas supply piping system at test
pressure equal to or less than 1/2 psig (3.5 kPa) or 14" W.C.
If the piping system is to be tested at pressures in excess of
1/2 psig (3.5 kPa), the furnace and its appliance main gas
valve must be disconnected from the gas supply piping
system.
After gas piping is complete, carefully check all piping
connections (factory and field) for gas leaks. Use a leak
detecting solution or other preferred means. Some soaps
used for leak detection are corrosive to certain metals.
Carefully rinse piping thoroughly after leak detection has
been completed.
Failure to follow the safety warnings exactly could result
in serious injury, death, or property damage.
Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifically
for the detection of leaks to check all connections. A
fire or explosion may result causing property damage,
personal injury, or loss of life.
FIRE OR EXPLOSION HAZARD
WARNING
The gas valve supplied with this furnace is rated at 1/2
psig maximum. Any higher pressure may rupture the
pressure regulator diaphragm and may cause overfiring
of the burners and improper burner operation. The
overfiring may result in the creation of carbon monoxide
which could cause asphyxiation.
WARNING
Gas Piping Connection
Figure 35
Manual Gas Valve
Union
Tee
Drip Leg
Cap
1/8" NPT Plugged Tapping
Manual Gas Valve
Union
Tee
Drip Leg
Cap
1/8" NPT Plugged Tapping
Upflow
Counterflow
Horizontal
Installation
