Confined Space

A confined space is an area with a volume less than 50 cu- bic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the combined input rating of all appliances installed in that space. This definition includes furnace closets or small equipment rooms.

When the furnace is installed so that supply ducts carry air circulated by the furnace to areas outside the space contain- ing the furnace, the return air must be handled by ducts which are sealed to the furnace casing and which terminate outside the space containing the furnace. This is especially important when the furnace is mounted on a platform in a confined space such as a closet or small equipment room. Even a small leak around the base of the unit at the platform or at the return air duct connection can cause a potentially dangerous negative pressure condition. Air for combustion and ventilation can be brought into the confined space either from inside the building or from outside.

EQUIPMENT IN CONFINED

SPACE ALL AIR FROM INSIDE

CHIMNEY

OR GAS

VENT

WATER

HEATER

FURNACE

OPENINGS

(To Adjacent

Room)

NOTE − Each opening shall have a free area of at least one square inch (645 mm2) per 1,000 Btu (.29 kW) per hour of the total input rat- ing of all equipment in the enclosure, but not less than 100 square inches (64516 mm2).

FIGURE 2

Air from Inside

If the confined space that houses the furnace adjoins a space categorized as unconfined, air can be brought in by providing two permanent openings between the two spaces. Each opening must have a minimum free area of 1 square inch (645 mm2) per 1,000 Btu (.29 kW) per hour of total input rating of all gas−fired equipment in the confined space. Each opening must be at least 100 square inches (64516 mm2). One opening shall be within 12 inches (305

mm)of the top of the enclosure and one opening within 12 inches (305 mm) of the bottom. See figure 2.

Air from Outside

If air from outside is brought in for combustion and ventila- tion, the confined space must have two permanent open- ings. One opening shall be within 12 inches (305 mm) of the top of the enclosure and one opening within 12 inches (305

mm)of the bottom. These openings must communicate di- rectly or by ducts with the outdoors or spaces (crawl or at- tic) that freely communicate with the outdoors or indirectly through vertical ducts. Each opening shall have a minimum free area of 1 square inch (645 mm2) per 4,000 Btu (1.17 kW) per hour of total input rating of all equipment in the en- closure. See figures 3 and 4. When communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 square inch (645 mm2) per 2,000 Btu (.56 kW) per total input rating of all equipment in the enclosure. See figure 5.

When ducts are used, they shall be of the same cross−sec- tional area as the free area of the openings to which they connect. The minimum dimension of rectangular air ducts shall be no less than 3 inches (75 mm). In calculating free area, the blocking effect of louvers, grilles, or screens must be considered. If the design and free area of protective cov- ering is not known for calculating the size opening required, it may be assumed that wood louvers will have 20 to 25 per- cent free area and metal louvers and grilles will have 60 to 75 percent free area. Louvers and grilles must be fixed in the open position or interlocked with the equipment so that they are opened automatically during equipment operation.

Page 7

Page 6 Page 8
Page 7
Image 7
Lennox International Inc DAVE LENNOX SIGNATURE COLLECTION GAS FURNACE Equipment in Confined Space ALL AIR from Inside
Page 6 Page 8

DAVE LENNOX SIGNATURE COLLECTION GAS FURNACE, SL280DFV specifications

Lennox International Inc has made a significant mark in the heating, ventilation, and air conditioning (HVAC) industry, known for its commitment to innovation and energy efficiency. One of its standout products is the SL280DFV model, a high-efficiency gas furnace designed to meet the needs of modern homes.

The SL280DFV boasts an impressive Annual Fuel Utilization Efficiency (AFUE) rating of up to 80%. This rating indicates that the furnace converts 80% of the fuel it consumes into usable heat, making it a cost-effective choice for homeowners. The high efficiency not only reduces energy bills but also lessens the environmental impact by minimizing greenhouse gas emissions.

One of the key features of the SL280DFV is its two-stage gas valve operation. This technology allows the furnace to operate at two levels of heating output: low stage for milder days and high stage for extremely cold temperatures. This adaptability enhances comfort by maintaining more consistent indoor temperatures while also saving energy when full power is unnecessary.

Another innovative aspect of the SL280DFV is its variable-speed blower motor. This smart technology enables the furnace to adjust airflow based on the heating needs of a home, which promotes quiet operation and improved temperature consistency throughout living spaces.

The SL280DFV is equipped with a durable heat exchanger that is designed to withstand the rigors of daily use, contributing to the unit’s longevity. Additionally, the furnace features a smart ignition system that ensures reliable start-ups, so homeowners can depend on it through the coldest winter nights.

Safety is also a priority in the design of the SL280DFV. It includes various safety features such as a built-in flame sensor and advanced venting system, designed to avert hazardous situations and ensure optimal operation.

Furthermore, Lennox offers convenient installation and maintenance support, making the SL280DFV not only an efficient heating solution but also a practical choice for homeowners. With its blend of advanced technology, high efficiency, and reliability, the Lennox SL280DFV is an appealing option for those looking to upgrade their home’s heating system, promising comfort and peace of mind for many winters to come.
Top Page Image Contents