15
GAS SUPPLY AND 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 B149.1 or .2) Installation Codes.
IMPORTANT NOTES:
• 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 12
(page 16). 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.
• 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.
• Flexible gas connectors are not recommended for
this type of furnace but may be used if allowed by
local jurisdiction. The fl exible gas connector must
be agency approved and certifi ed for the type of
gas being used. Only new fl exible connectors may
be used. Do not reuse old fl exible gas connectors.
• A drip leg should be installed in the vertical pipe
run to the unit (Figure 12).
Table 7 (page 32) lists gas pipe capacities for standard
pipe sizes as a function of length in typical applications
based on nominal pressure drop in the line.
The furnace may be installed for either left or right side
gas entry. When connecting the gas supply, provide
clearance between the gas supply line and the entry hole
in the furnace casing to avoid unwanted noise and/or
damage to the furnace. Typical gas hookups are shown
in Figure 12.
Leak Check
WARNING:
FIRE OR EXPLOSION HAZARD
Never test for gas leaks with an open fl ame.
Check all connections using a commercially
available soap solution. A fi re 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 furnace is complete, all
connections must be tested for gas leaks. This includes
pipe connections at the main gas valve, emergency shutoff
valve and fl exible gas connectors (if applicable). The 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.
IMPORTANT NOTE: When pressure testing gas supply
lines at pressures greater than 1/2 psig (14 inch W.C.),
the gas supply piping system must be disconnected
from the furnace to prevent damage to the gas control
valve. If the test pressure is less than or equal to 1/2
psig (14 inch W.C.), close the manual shut-off valve.
High Altitude Application
High altitude conversion with this furnace depends on the
installation altitude and the heating value of the gas. The
installation of this furnace at altitudes above 2,000 feet
must meet the requirements of the National Fuel Gas
Code or local jurisdiction. In Canada, the requirements for
high altitude are different and governed by CGA B149.1.
Please consult your local code authority.
WARNING:
The reduction of input rating necessary for high
altitude installation may only be accomplished
with factory supplied orifi ces. Do not attempt
to drill out orifi ces in the fi eld. Improperly
drilled orifi ces may cause fi re, explosion,
carbon monoxide poisoning, personal injury
or death.
The furnaces are shipped from the factory with orifi ces
and gas regulator settings for natural gas operation at sea
level altitudes. At 2000 feet, the NFGC requires that this
appliance be derated 4% for each 1,000 feet of altitude.
For example, at 2,000 feet the input needs to be reduced
8%, at 3,000 feet (12%), etc. This deration is in reference
to the input rate and gas heating value at sea level.
To derate the furnace requires knowing the heating value of
the gas at the installation site. Heating values at particular
job sites vary for two reasons:
1. The chemical mixture of the gas varies from region
to region and is expressed as the “sea level heating
value”.
2. The heating value varies by altitude. For this reason,
especially in high altitude areas, the local gas utility
specifi es the heating value at the residence’s gas
meter as the “local value”.
For added fl exibility, two tables have been provided for
natural gas installations with HIGH or LOW heating
values at sea level. Tables 10 and 11 (page 34) contain
the orifi ce sizes and manifold pressure to use at various
altitudes. Table 10 (High) is for natural gas installations
