Service Guide
SYSTEM OPERATION
18
Even if none of those three conditions exist which require
additional liner insulation, the installer may wish to consider
it if:
• The local climate is very cold.
• The chimney is very tall.
• The vent connectors used are very long or have a large
number of elbows.
• Local experience indicates that exible liners installed
without insulation are likely to have condensation
problems.
Insulation must be selected and installed in accordance with
the liner manufacturer’s instructions.
Finally, cap the chimney and terminate the liner in accordance
with the liner manufacturer’s instructions.
Horizontal applications, in particular, may dictate many of
the installation’s specics such as airow direction, ductwork
connections, and ue pipe connections.
Furnaces have provisions allowing for electrical and gas
line connections through either side panel. In horizontal
applications the connections can be made either through the
“top” or “bottom” of the furnace.
SS RR RS JR R R
RR RS KS R S
RR KS
S SR S RR R R
RSS S RR Q SR R SR
This furnace is shipped from the factory congured for natural
gas at standard altitude. Propane gas installations require
an orice change to compensate for the energy content
dierence between natural and propane gas.
High altitude installations may require both a pressure switch
and an orice change. These changes are necessary to
compensate for the natural reduction in the density of both
the gas fuel and the combustion air at higher altitude.
Refer to the Accessories Charts in this manual or product
Specification Sheet for a tabular listing of appropriate
manufacturer’s kits for propane gas and/or high altitude
installations. The indicated kits must be used to insure
safe and proper furnace operation. All conversions must be
performed by a qualied installer, or service agency.
R S SRS RS JR R
R R SRS S
S
R S R S
R SS S S R SSR
S RR S
KS SS RS SRS
RS JR R XSR RS
R X
The furnace rating plate includes the approved furnace gas
input rating and gas types. The furnace must be equipped
to operate on the type of gas applied. This includes any
conversion kits required for alternate fuels and/or high altitude.
R R R R Q
S S RSSR S S S R
R S S R S R
Inlet gas supply pressures must be maintained within the
ranges specied below. The supply pressure must be constant
and available with all other household gas red appliances
operating. The minimum gas supply pressure must be
maintained to prevent unreliable ignition. The maximum must
not be exceeded to prevent unit overring.
Natural Gas Minimum: 4.5" w.c. Maximum: 10.0" w.c.
Propane Gas Minimum: 11.0" w.c. Maximum: 13.0" w.c.
When this furnace is installed at high altitude, the appropriate
High Altitude orice kit must be applied. This is required due
to the natural reduction in the density of both the gas fuel and
combustion air as altitude increases. The kit will provide the
proper design certied input rate within the specied altitude
range.
High altitude kits are purchased according to the installation
altitude and usage of either natural or propane gas. Refer
to the product Specification Sheet or Technical Manual
for a tabular listing of appropriate altitude ranges and
corresponding manufacturer’s high altitude (Natural, Propane
gas, and/or Pressure Switch) kits.
Do derate the furnace by adjusting the manifold pressure
to a lower pressure than specied on the furnace rating plate.
The combination of the lower air density and a lower manifold
pressure will prohibit the burner orice from drawing the proper
amount of air into the burner. This may cause incomplete
combustion, ashback, and possible yellow tipping.
In some areas the gas supplier may articially derate the gas
in an eort to compensate for the eects of altitude. If the
gas is articially derated, the appropriate orice size must be
determined based upon the BTU/ft
3
content of the derated
gas and the altitude. Refer to the National Fuel Gas Code,
NFPA 54/ANSI Z223.1, and information provided by the gas
supplier to determine the proper orice size.