19
GAS SUPPLY & PIPING
• All gas piping must be installed in compliance with
local codes and utility regulations. In the absence
of local codes the gas line installation must comply
with the latest edition of the National Fuel Gas Code
ANSI Z223.1 or CAN/CGA B149 Installation Codes.
• Some local codes require the installation of a manual
main shut-off valve and ground joint union external
to the furnace as shown in Figure 10. The shut-off
valve should be readily accessible for service and/
or emergency use. Consult the local utility or gas
supplier for additional requirements regarding
placement of the manual main gas shut-off.
•
The manifold pressure must be set to the appropriate
value for your installation. Refer to the Manifold
Pressure Adjustment section (page 22) for
adjustment instructions.
• Gas piping must never run in or through air ducts,
chimneys, gas vents, or elevator shafts.
• Compounds used to seal joints on gas piping must
be resistant to the actions of LP propane gas.
• The main gas valve and main power disconnect to
the furnace must be properly labeled by the installer
in case emergency shutdown is required.
• An 1/8 inch NPT plugged tap must be installed in
the gas line immediately upstream of the gas supply
connection to the furnace for use when measuring
the gas supply pressure. The plug should be readily
accessible for service use.
• A drip leg should be installed in the vertical pipe
run to the unit (Figure 10).
This unit only has right side gas entry. When connecting
the gas, provide clearance between the gas supply line
and the entry hole in the unit’s casing to avoid unwanted
noise and/or damage to the unit. A typical gas service
hookup is shown in Figure 10.
Table 13 (page 29) lists gas pipe capacities for standard
pipe sizes as a function of length in typical applications
based on nominal pressure drop in the line.
Leak Check
WARNING:
FIRE OR EXPLOSION HAZARD
Never test for gas leaks with an open flame. Check
all connections using a commercially available
soap solution. A fire or explosion may result
causing property damage, personal injury or
loss of life. Failure to follow the safety warnings
exactly could result in serious injury, death or
property damage.
After the gas piping to the unit is complete, all connections
must be tested for gas leaks. This includes pipe connections
at the main gas valve, emergency shutoff valve and
other gas connectors. A soap and water solution can be
applied on each joint or union using a small paintbrush.
If any bubbling is observed, the connection is not sealed
adequately and must be retightened. Repeat the tightening
and soap check process until bubbling ceases.
•
If pressure testing the gas supply lines at pressures
greater than 1/2 psig (14 inches WC), the unit must
be disconnected from the gas supply piping system
to prevent damage to the gas valve.
•
If the test pressure is less than or equal to 1/2 psig
(14 inches WC), the unit must be isolated from the
gas supply line by closing the manual shut-off valve.
High Altitude Conversion
Conversion of this unit must be performed by qualified
service personnel, using only approved parts. All
installations must be made in accordance with the National
Fuel Gas Code or with local jurisdiction codes.
If installing this unit above 2,000 feet, the input rate must
be reduced 4% per 1,000 feet of altitude (Example: 12%
at 3,000 feet, 16% at 4,000 feet, etc).
NOTE:
Deration is
necessary to compensate for low atmospheric pressure
at high altitudes.
WARNING:
The reduction of input rating necessary for high
altitude installation may only be accomplished
with factory supplied orifices. Do not attempt to
drill out orifices in the field. Improperly drilled
orifices may cause fire, explosion, carbon
monoxide poisoning, personal injury or death.
High altitude conversion can be field performed by a
simple adjustment of manifold pressure or a change of
the orifices (if necessary) as described on page 22. The
changes required depend on the installation altitude and
the heating value of the gas (based on sea level) which
can be obtained from your local gas utility.
Ground
Joint
Union
Dripleg
Shut-Off Valve
with 1/8 NPT
plugged tap
Burner
Assembly
Manifold
Some utilities
require Shut-Off
Valve to be
4 to 5 feet
above floor
Automatic Gas Valve
(with manual shut-off)
Figure 10. Typical Gas Hookup - Right Side Entry
