Nordyne G6RC 90+, G6RL 90+, G6RD 93+ Circulating AIR Supply, Furnace on a Concrete Slab

Concrete	Furnace
Floor
	Sheet
	Metal
	Plenum

Figure 4. Furnace on a Concrete Slab

18.75"	13.25"
19.63"	19.63"
Hole in	Hole in
Floor	Floor
G6RL 080/100	G6RL 040/060

Figure 5. Opening in Wood Floor

Downflow	Furnace	Wood
Sub-base		Floor
	Sheet
	Metal
	Plenum

Figure 6. Furnace on a Wood Floor

CIRCULATING AIR SUPPLY

Plenums and air ducts must be installed in accordance with the Standard for the Installa- tion of Air Conditioning and Ventilating Systems (NFPA No. 90A) or the Standard for the Installa- tion of Warm Air Heating and Air Conditioning Systems (NFPA No. 90B).

		* Smaller
		dimensions for
	18.75"
		G6RL 040/060
or 13.25"*

	9.25"
			2.0"
16.75"	28.38"	densitylb3
or 11.25"*
		fiberglassthick
1.50"			19.63"
	1.58"	1 inch
19.75"			3"
or 14.25"*

Figure 7. Downflow Sub-Base Dimensions

If outside air is utilized as return air to the furnace for ventilation or to improve indoor air quality, the system must be designed so that the return air to the furnace is not less than 50°F (10°C) during heating operation. If a combination of indoor and outdoor air is used, the ducts and damper system must be designed so that the return air supply to the furnace is equal to the return air supply under normal, indoor return air applications.

When a cooling system is installed which uses the furnace blower to provide airflow over the indoor coil, the coil must be installed down- stream (on the outlet side) or in parallel with the furnace.

If a cooling system is installed in parallel with the furnace, a damper must be installed to prevent chilled air from entering the furnace and con- densing on the heat exchanger. If a manually operated damper is installed, it must be de- signed so that operation of the furnace is pre- vented when the damper is in the cooling posi- tion and operation of the cooling system is prevented when the damper is in the heating position.

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