Sears N8MPL125J20B1, N8MPN075F16B1 Ventilation Air, Category I Safe Venting Requirements

The Standard Method may be used, if the space has no less vol- ume than 50 cubic feet per 1,000 BTUH of the maximum input rat- ings for all gas appliances installed in the space. The standard method permits indoor air to be used for combustion and ventila- tion air.

The Known Air Infiltration Rate Method shall be used if the in- filtration rate is known to be less than 0.40 air changes per hour

(ACH) and equal to or greater than 0.10 ACH. Infiltration rates greater than 0.60 ACH shall not be used. The minimum required volume of the space varies with the number of ACH and shall be

determined per Table 2 or Equations 1 and 2. Determine the minimum required volume for each appliance in the space, and add the volumes together to get the total minimum required vol- ume for the space.

	MINIMUMSPACEVOLUMEFOR100%COMBUSTION
				ANDVENTILATIONAIR FROMINDOORS (ft 3)
	Other Than Fan-Assisted Total					Fan- assistedTotal
..............................................................		(1,OOO'sBtuh)			75	I	(1,000'sBtuh)	125	I	180
ACH	30	40	50	50			100
0.60	1,050	1,400	1,750	1,250	1,875		2,500	3,125		3,750
0.50	1,260	1,680	2,100	1,500	2,250		3,000	3,750		4,500
0.40	1,575	2,100	2,625	1,875	2,813		3,750	4,688		5,625
0.30	2,100	2,800	3,500	2,500	3,750		5,000	6,250		7,500
0.20	3,150	4,200	5,250	3,750	5,625		7,500	9,375		11,250
0.10	6,300	8,400	10,500	7,500	11,250		15,000	18250		22,500
0.00	NP	NP	NP	NP	NP		NP	NP		NP

NP = Not Permitted

Table 2 Minimum Space Volumes were determined by using the following equations from the National Fuel Gas Code ANSI Z223.1/NFPA 54-2002, 8.3.3.2:

1. For other than fan-assisted appliances such as a draft

hood-equipped water heater,

	21 ft 3	(	I other	)
Volume other =	ACH		1000 Btu / hr

2.For fan-assisted appliances such as this furnace,

	15ft3	(	Iran	)
Volume fan =	ACH		1000 Btu / hr

If:

[ other= combined input of all other than fan-assisted appliances in Btu/hr

[fan = combined input of all fan-assisted appliances in Btu/hr

main open and NOT have any means of being closed off. Ven- tilation openings to outdoors MUST be at least 1 square inch of free area per 4,000 BTUH of total input rating for all gas ap- pliances in the space.

In spaces that use the Indoor Combustion Air Method, in- filtration should be adequate to provide air for combustion, ventilation and dilution of flue gases. However, in buildings

with unusually tight construction, additional air MUST be pro- vided using the methods described in section titled Outdoor

Combustion Air Method:

Unusually tight construction is defined as Construction with:

1.Walls and ceilings exposed to the outdoors have a con-

tinuous, sealed vapor barrier. Openings are gasketed or sealed and

2.Doors and openable windows are weather stripped and

3.Other openings are caulked or sealed. These include joints around window and door frames, between sole

plates and floors, between wall-ceiling joints, between

wall panels, at penetrations for plumbing, electrical and gas lines, etc.

ACH = air changes per hour (ACH shall not exceed 0.60.)

The following requirements apply to the Standard Method and to

the Known Air Infiltration Rate Method.

•Adjoining rooms can be considered part of a space, if there are no closable doors between rooms.

•An attic or crawl space may be considered a space that freely

communicates with the outdoors provided there are adequate ventilation openings directly to outdoors. Openings MUST re-

Ventilation Air

Some provincial codes and local municipalities require ventilation or make-up air be brought into the conditioned space as replace- ment air. Whichever method is used, the mixed return air tempera-

ture across the heat exchanger MUST not fall below 60 °

continuously, or 55 ° on an intermittent basis so that flue gases will

not condense excessively in the heat exchanger. Excessive con- densation will shorten the life of the heat exchanger and possibly void your warranty.

5.Gas Vent Installation

CARBON MONOXIDE POISONING, FIRE AND EXPLOSION HAZARD.

Failure to properly vent this furnace could result in death, personal injury and/or property damage.

Read and follow all instructions in this section.

Install the vent in compliance with codes of the country having ju- risdiction, local codes or ordinances and these instructions.

This Category [ furnace is fan-assisted.

Category ] furnace definition: A central furnace which operates with a non-positive vent static pressure and with a flue loss not less than 17 percent. These furnaces are approved for common- venting and multi-story venting with other fan-assisted or draft hood-equipped appliances in accordance with the NFGC or

NSCNGPIC

Category I Safe Venting Requirements

Category ] furnace vent installations shall be in accordance with Parts 10 and 13 of the National Fuel Gas Code (NFGC), ANSI

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