Bryant 120 instruction manual AIR for Combustion Ventilation, Furnace Corrosion Hazard

312A

equipped with means to prevent operation of either unit unless the damper is in the full-heat or full-cool position.

AIR FOR COMBUSTION AND

VENTILATION

Provisions for adequate combustion, ventilation, and dilution air must be provided in accordance with:

U.S. installations: Section 8.3 of the NFGC, Air for Combustion and Ventilation, and applicable provisions of the local building codes.

Canadian installations: Part 8 of the CAN/CSA-B149.1-05, Venting Systems and Air Supply for Appliances and all authorities having jurisdiction.

!CAUTION

FURNACE CORROSION HAZARD

Failure to follow this caution may result in furnace damage.

Air for combustion must not be contaminated by halogen compounds, which include fluoride, chloride, bromide, and iodide. These elements can corrode heat exchangers and shorten furnace life. Air contaminants are found in aerosol sprays, detergents, bleaches, cleaning solvents, salts, air fresheners, and other household products.

!WARNING

CARBON MONOXIDE POISONING HAZARD

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 cubic feet per 1,000 Btuh input rating for all gas appliances installed in the space.

SSpaces having less than 50 cubic feet per 1,000 Btuh require the Outdoor Combustion Air Method.

SSpaces having at least 50 cubic feet 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 combustion, ventilation, and dilution of flue gases using permanent horihorizontal 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.

a.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.

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

c.TWO HORIZONTAL DUCTS require 1 square inch 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.

d.TWO OPENINGS OR VERTICAL DUCTS require 1 square inch 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 connectors in the space.

Table 2 – Minimum Free Area Required for Each Combustion Air Opening or Duct to Outdoors

		TWO HORIZONTAL DUCTS				SINGLE DUCT OR OPENING			TWO OPENINGS OR VERTICAL
									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)
		Free Area of	Round Duct			Free Area of		Round Duct	Free Area of	Round Duct
	Opening and Duct					Opening and Duct			Opening and Duct
			(in. Dia)					(in. Dia)		(In. Dia)
		(Sq. In.)				(sq. In.)			(Sq. In.)
44,000		22		6		14.7		5	11	4
66,000		33		7		22		6	16.5	5
88,000		44		8		29.3		7	22	6
110,000		55		9		36.7		7	27.5	6
132,000		66		10		44		8	33	7
154,000		77		10		51.3		9	38.5	8
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

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