If it is necessary for the installer to supply additional line voltage wiring to the inside of the furnace, the wiring must conform to all local codes, and have a minimum temperature rating of 105°C. All line voltage wire splices must be made inside the furnace junction box.
The integrated control module electronic air cleaner terminals (EAC) are energized with 115 volts whenever the circulator blower is en- ergized.
24 VOLT HUMIDIFIER
The yellow wire connected to the I.D. Blower pressure switch is powered anytime the pressure switch is closed and provides 24 VAC humidifier control. Remove the yellow wire and connect a field supplied jumper wire with a “piggyback” terminal to the pressure switch terminal. Reconnect the yellow wire to the “piggyback” ter- minal on the jumper wire and then connect the 24 VAC line of the humidifier to the stripped end of the jumper wire. Using a wire nut or a
NALS.
XII. GAS SUPPLY AND PIPING
GENERAL
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.
CAUTION
TO PREVENT UNRELIABLE OPERATION OR EQUIPMENT DAMAGE, THE INLET GAS SUPPLY PRESSURE MUST BE AS SPECIFIED ON THE UNIT RATING PLATE WITH ALL OTHER HOUSEHOLD GAS FIRED APPLIANCES OPERATING.
Inlet gas supply pressures must be maintained within the ranges specified below. The supply pressure must be constant and avail- able with all other household gas fired appliances operating. The minimum gas supply pressure must be maintained to prevent unreliable ignition. The maximum must not be exceeded to pre- vent unit overfiring.
Inlet Gas Supply Pressure
Natural Gas | Minimum: | 4.5" w.c. | Maximum: | 10.0" w.c. |
Propane Gas | Minimum: | 11.0" w.c. | Maximum: | 13.0" w.c. |
HIGH ALTITUDE DERATE
When this furnace is installed at high altitude, the appropriate High Altitude orifice kit must be applied. This is required due to the natural reduction in the density of both the gas fuel and combus- tion air as altitude increases. The kit will provide the proper design certified input rate within the specified altitude range.
High altitude kits are purchased according to the installation alti- tude and usage of either natural or propane gas. Contact your distributor for a tabular listing of appropriate altitude ranges and corresponding manufacturer’s high altitude (Natural, Propane Gas, and/or Pressure Switch) kits.
Do not derate the furnace by adjusting the manifold pressure to a lower pressure than specified on the furnace rating plate. The combination of the lower air density and a lower manifold pressure will prohibit the burner orifice from drawing the proper amount of air into the burner. This may cause incomplete combustion, flash- back, and possible yellow tipping.
In some areas the gas supplier may artificially derate the gas in an effort to compensate for the effects of altitude. If the gas is artificially derated, the appropriate orifice size must be determined based upon the BTU/ft3 content of the derated gas and the altitude. Refer to the National Fuel Gas Code, NFPA 54/ANSI Z223.1, and information pro- vided by the gas supplier to determine the proper orifice size.
A different pressure switch may be required at high altitude regardless of the BTU/ft3 content of the fuel used. Contact your distributor for a tabular listing of appropriate altitude ranges and corresponding manufacturer’s pressure switch kits.
PROPANE GAS CONVERSION
WARNING
POSSIBLE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH MAY OCCUR IF THE CORRECT CONVERSION KITS ARE NOT INSTALLED. THE APPROPRIATE KITS MUST BE APPLIED TO ENSURE SAFE AND PROPER FURNACE OPERATION. ALL CONVERSIONS MUST BE PERFORMED BY A QUALIFIED INSTALLER OR SERVICE AGENCY.
This unit is configured for natural gas. The appropriate manufacturer’s propane gas conversion kit, must be applied for propane gas installations. Refer to the Section VIII, Propane Gas / High Altitude Installations section for details.
Consult the furnace Specification Sheet for a listing of appropirate kits. The indicated kits must be used to insure safe and proper furnace operation. All conversions must be performed by a quali- fied installer or service agency.
GAS VALVE
This unit is equipped with a 24 volt gas valve controlled during furnace operation by the integrated control module. As shipped, the valve is configured for natural gas. The valve is field convertible for use with propane gas by replacing the regulator spring with a propane gas spring from an appropriate manufacturer’s propane gas conversion kit. Taps for measuring the gas supply pressure and manifold pressure are provided on the valve.
The gas valve has a manual ON/OFF control located on the valve itself. This control may be set only to the “ON” or “OFF” position. Refer to the lighting instructions label or Section XIV, Startup Pro- cedure & Adjustment for use of this control during start up and shut down periods.
GAS PIPING CONNECTIONS
GENERAL
CAUTION
TO AVOID POSSIBLE UNSATISFACTORY OPERATION OR EQUIPMENT DAMAGE DUE TO UNDERFIRING OF EQUIPMENT, USE THE PROPER SIZE OF NATURAL/PROPANE GAS PIPING NEEDED WHEN RUNNING PIPE FROM THE METER/TANK TO THE FURNACE.
When sizing a trunk line, be sure to include all appliances which will operate simultaneously.
The gas piping supplying the furnace must be properly sized based on the gas flow required, specific gravity of the gas, and length of the run. The gas line installation must comply with local codes, or in their absence, with the latest edition of the National Fuel Gas Code, NFPA 54/ANSI Z223.1.
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