All field wiring must conform to applicable codes. Connections should be made as shown in the following illustration.
Control Module
NOTE: Adjusting the minimum supply pressure below the limits in the above table could lead to unreliable ignition. Gas input to the burners must not exceed the rated input shown on the rating plate. Overfiring of the furnace can result in premature heat
Hot 120 VAC
EAC |
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| Line | Transformer |
Optional { Accessories
Neutral 120 VAC
Hum | Hum |
| EAC | Transformer | Line | |
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Air Cleaner
Humidifier
exchanger failure. Gas pressures in excess of 13 inches water column can also cause permanent damage to the gas valve.
IMPORTANT NOTE: The furnace will naturally derate itself with altitude. Do not attempt to increase the firing rate by changing orifices or increasing the manifold pressure. This can cause poor combustion and equipment failure.
At all altitudes, the manifold pressure must be within 0.3 inches w.c. of that listed in the Product Data Book applicable to your model* for the fuel used. At all altitudes and with either fuel, the air temperature rise must be within the range listed on the furnace
Figure 15 - Accessories Wiring
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 humidifier terminals (HUM) are energized with 115 volts whenever the induced draft blower is energized. The integrated control module electronic air cleaner terminals (EAC) are energized with 115 volts whenever the circulator blower is energized.
24 VAC HUM
1.24 VAC Hum - A ¼” insulated male quick connect terminal on the pressure switch provides 24 VAC humidifier control. this terminal will be powered any time the pressure switch is closed. To connect 24 VAC hum, connect 24vac line of humidifier to piggyback on the pressure switch. The com side of the humidfier to C on the terminal strip on the control board (or to com side to 24VAC transformer). Do not connect 115V humidifier to these terminals.
IX. 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 in the following table. The supply pressure must be constant and available 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 prevent unit overfiring.
Inlet Gas Supply Pressure
Natural Gas | Minimum: 5.0" w.c. | Maximum:10.0" w.c. |
Propane Gas | Minimum: 11.0" w.c. | Maximum:13.0" w.c. |
nameplate. Should this appliance be converted to LP, refer to the instructions included in the factory authorized LP conversion kit
HIGH ALTITUDE DERATE
When this furnace is installed at high altitude, the appropriate High Altitude orifice kit must be applied. The furnace is supplied with orifices sized for natural gas at altitudes up to 2,000 feet using a heating value of approximately 1,000 Btu/hr, and should not normally require change. If for use at altitudes in excess of 2,000 feet, refer to the instructions included in the factory authorized high altitude kit
It is important to check and adjust the input rate of the furnace to prevent an overfiring situation. Overfiring can cause premature heat exchanger failure. The input is controlled by the supply pressure, orifice size, manifold pressure and heating (calorific) value of the gas.
The supply pressure must be measured with this and all other gas burning appliances in operation. The supply pressure must be adjusted to the pressure range stated on the series and rating plate. Applications for altitudes in excess of 2,000 feet usually require an orifice change. The orifices must be selected using the table below. The furnace derate is 4% for each 1,000 feet above sea level. This table is based upon a heating value of approximately 1,000 Btu/ft3
ALTITUDE | NAT. GAS | |
ORIFICE SIZE | ||
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0 - 2,000 | #43 | |
3,000 | #44 | |
4,000 | #44 | |
5,000 | #45 | |
6,000 | #45 | |
7,000 | #46 | |
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The input to the furnace must be checked AFTER reorificing.
For altitudes above 7,000 feet, refer to appropriate section of the National Fuel Gas Code, ANSI Z223.1. To calculate the input of the furnace for installations in altitudes over 2,000 - 7,000 feet, use the following formula:
Corrected Input = Series & Rating Plate Input - (Altitude X .04) X (Series & Rating Plate Input / 1000)
Example:
Corrected input for a 90,000 Btu/hr. appliance installed at an altitude of 6,000 ft. utilizing natural gas with a heating value of
17 | 12/04 | |
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