Carbon Monoxide Poisoning Hazard

310AAV

!WARNING

Failure to follow this warning could result in personal injury or death.

The operation of exhaust fans, kitchen ventilation fans, clothes dryers, attic exhaust fans or fireplaces could create a NEGATIVE PRESSURE CONDITION at the furnace. Make-up air MUST be provided for the ventilation devices, in addition to that required by the furnace. Refer to Carbon Monoxide Poisoning Hazard warning in venting section of these instructions to determine if an adequate amount of make-up air is available.

The requirements for combustion and ventilation air depend upon whether or not the furnace is located in a space having a volume of at least 50 cu/ft. per 1,000 Btuh input rating for all gas appliances installed in the space.

SSpaces having less than 50 cu/ft. per 1,000 Btuh re- quire the OUTDOOR COMBUSTION AIR METHOD.

SSpaces having at least 50 cu/ft. per 1,000 Btuh may use the INDOOR COMBUSTION AIR, STANDARD or

KNOWN AIR INFILTRATION METHOD.

Outdoor Combustion Air Method

1.Provide the space with sufficient air for proper combus- tion, ventilation, and dilution of flue gases using perman- ent horizontal or vertical duct(s) or opening(s) directly communicating with the outdoors or spaces that freely communicate with the outdoors.

2.Fig. 7 illustrates how to provide TWO OUTDOOR OPENINGS, one inlet and one outlet combustion and ventilation air opening, to the outdoors.

e. One opening MUST commence within 12 in. (300 mm) of the ceiling and the second opening MUST commence within 12 in. (300 mm) of the floor.

f.Size openings and ducts per Fig. 7 and Table 2.

g.TWO HORIZONTAL DUCTS require 1 sq./in. of free area per 2,000 Btuh (1,100 mm2/kW) of combined input for all gas appliances in the space per Fig. 7 and Table 2.

h.TWO OPENINGS OR VERTICAL DUCTS require 1 sq./in. of free area per 4,000 Btuh (550 mm2/kW) for combined input of all gas appliances in the space per Fig. 7 and Table 2.

3.ONE OUTDOOR OPENING requires:

a.1 square inch of free area per 3,000 Btuh (734 mm2/kW) for combined input of all gas appliances in the space per Table 2 and

b.Not less than the sum of the areas of all vent connect- ors in the space.

The opening shall commence within 12 in. (300 mm) of the ceiling. Appliances in the space shall have clearances of at least 1 in. (25 mm) from the sides and back and 6 in. (150 mm) from the front. The opening shall directly communicate with the outdoors or shall communicate through a vertical or horizontal duct to the outdoors or spaces (crawl or attic) that freely communicate with the outdoors.

Indoor Combustion Air NFPA & AGA

Standard and Known-Air-Infiltration Rate Methods

Indoor air is permitted for combustion, ventilation, and dilution, if the Standard or Known-Air-Infiltration Method is used.

!WARNING

CARBON MONOXIDE POISONING HAZARD Failure to follow this warning could result in death and/or personal injury.

Many homes require air to be supplied from outdoors for furnace combustion, ventilation, and dilution of flue gases. The furnace combustion air supply must be provided in accordance with this instruction manual.

Table 2—Minimum Free Area Required for Each Combustion Air Opening of Duct to Outdoors

	TWO HORIZONTAL DUCTS						SINGLE DUCT OR OPENING				TWO OPENINGS OR VERTICAL
	TWO HORIZONTAL DUCTS						SINGLE DUCT OR OPENING					DUCTS
												DUCTS
FURNACE		(1 SQ. IN./2,000 BTUH)					(1 SQ. IN./3,000 BTUH)				(1 SQ. IN./4,000 BTUH)
INPUT		(1,100 SQ. MM/KW)						(734 SQ. MM/KW)				(550 SQ. MM/KW)
(BTUH)
(BTUH)	Free Area of Open-		Round Duct				Free Area of Open-		Round Duct		Free Area of Open-		Round Duct
	ing and Duct		Dia.				ing and Duct		Dia.		ing and Duct		Dia.
	Sq. In. (Sq. mm)		In. (mm)				Sq. In. (Sq. mm)		In. (mm)		Sq. In. (Sq. mm)		In. (mm)

44,000	22	(14194)	6	(152)			14.7	(9484)	5 (127)		11	(7096)	4 (102)
66,000	33	(21290)	7	(178)			22.0	(14193)	6 (152)		16.5	(10645)	5 (127)
88,000	44	(28387)	8	(203)			29.3	(18903)	7 (178)		22	(14193)	6 (152)
110,000	55	(35484)	9	(229)			36.7	(23677)	7 (178)		27.5	(17742)	6 (152)
132,000	66	(42580)	10	(254)			44 .0 (28387)		8 (203)		33	(21290)	7 (178)
154,000	77	(49677)	10	(254)			51.3	(33096)	9 (229)		38.5	(24839)	8 (203)

						EXAMPLES: Determining Free Area
FURNACE		WATER HEATER			TOTAL INPUT
110,000	+	30,000		=	(140,000 divided by 4,000)				= 35.0 Sq. In. for each two Vertical Ducts or Openings
66,000	+	40,000		=	(106,000 divided by 3,000)				= 35.3	Sq. In. for a Single Duct or Opening
88,000	+	30,000		=	(118,000 divided by 2,000)				= 59.0	Sq. In. for each of two Horizontal Ducts