Step 5: If Indoor Combustion Air is Used, Provide Air as Follows:

1) Buildings of other than unusually tight construction:

Unconfined Space– Natural infiltration into the boiler room will normally provide adequate air for combustion and ventilation without additional louvers or openings into boiler room.

Confined Space – Provide two openings into the boiler room, one near the floor and one near the ceiling. The top edge of the upper opening must be within 12” of the ceiling and the bottom edge of the lower opening must be within 12” of the floor (Fig 3).

•Each opening must have a free area of 1 square inch per 1000 BTU/hr input of all gas burning appliances in the boiler room. The minimum opening dimension is 3 inches. Minimum opening free area is 100 square inches per opening.

•If the total volume of both the boiler room and the room to which the openings connect is less than 50 cubic feet per 1000 BTU/hr of total appliance input, install a pair of identical openings into a third room. Connect additional rooms with openings until the total volume of all rooms is at least 50 cubic feet per 1000 BTU/hr of input.

•The “free area” of an opening takes into account the blocking effect of mesh, grills, and louvers. Where screens are used, they must be no finer than ¼” (4 x 4) mesh.

2)Buildings of unusually tight construction:

If at all possible, direct vent the boiler. Where the boiler must be installed in unusually tight construction and cannot be direct vented, openings must be installed between the boiler room and the outdoors or a ventilated space, such as an attic or crawl space, which communicates directly with the outdoors. Two openings are required. The top edge of the upper opening must be within 12 inches of the ceiling. The bottom edge of the lower opening must be within 12 inches of the floor. Size openings and ducts as follows:

•Vertical ducts or openings directly outdoors (Fig 4, Fig 5, Fig 6) – Each opening must have a free cross sectional area of

1 square inch per 4000 BTU/hr of the total input of all gas-fired appliances in the boiler room but not less than 100 square inches. Minimum opening size is 3 inches.

•Openings to outdoors via horizontal ducts (Fig 7) - Each opening must have a free cross sectional area of 1 square inch per 2000 BTU/hr of the total input of all gas fired appliances in the boiler room but not less than 100 square inches. Minimum opening size is 3 inches.

•The “free area” of an opening takes into account the blocking effect of mesh, grills, and louvers. Where screens are used, they must be no finer than ¼” (4 x 4) mesh.

FIGURE 3: BOILER INSTALLED IN A CONFINED SPACE - VENTILATION OR

COMBUSTION / VENTILATION AIR FROM INSIDE

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Crown Boiler CWD083, CWD220, CWD060, CWD165, CWD138, CWD193, CWD245 If Indoor Combustion Air is Used, Provide Air as Follows
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CWD193, CWD165, CWD245, CWD220, CWD110 specifications

Crown Boiler Company is well-known for its commitment to quality and performance in the heating industry. Among its extensive range of products, the Crown Boiler CWD series stands out for its reliability and efficiency. This series includes models CWD060, CWD083, CWD110, CWD138, and CWD220, each designed to meet diverse heating needs in residential and commercial applications.

One of the main features of the CWD series is its durable construction. Made with high-quality materials, these boilers are built to withstand the test of time. The cast iron heat exchanger delivers exceptional heat retention and efficiency, ensuring optimal performance even in demanding conditions. Additionally, the CWD models are equipped with a reliable standing pilot ignition system, which enhances user safety and operational reliability.

Another important characteristic of the Crown CWD series is its versatility in fuel options. These boilers can operate on either natural gas or propane, providing flexibility to homeowners and businesses depending on their preferred energy source. The ability to easily switch fuels makes these units adaptable to various heating applications, maximizing convenience for users.

Efficiency is a cornerstone of the Crown Boiler CWD series. With an AFUE rating of up to 85%, these boilers deliver substantial cost savings over the heating season. Their efficient operation not only lowers energy bills but also contributes to a reduced environmental impact, which is increasingly important in today’s energy-conscious world.

Crown’s innovative design features also include a low water cut-off and a built-in draft hood. The low water cut-off ensures safe operation by preventing the boiler from running dry, while the draft hood allows for optimal venting capabilities, minimizing the risk of dangerous flue gas build-up.

Maintenance is straightforward with the CWD series, thanks to its easy-access design. Routine service and inspections can be performed with minimal disruption, ensuring that the units maintain peak performance over their lifespan.

The Crown Boiler CWD060, CWD083, CWD110, CWD138, and CWD220 models exemplify the brand’s dedication to delivering high-quality heating solutions. With their impressive efficiency ratings, durable construction, versatile fuel options, and user-friendly features, these boilers represent a smart investment for anyone looking to enhance heating reliability and comfort in their space.
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