COMBUSTION & VENTILATION AIR

Provisions for combustion and ventilation air must be in accordance with Section 5.3, Air for Combustion and Ventilation, of the latest edition of the National Fuel Gas Code, ANSI Z223.1; in Canada, the latest edition of CGA Standard B149 Installation Code for Gas Burning Appliances and Equipment; or applicable provisions of the local building codes.

The equipment room must be provided with properly sized openings to assure adequate combustion air and proper ventilation when the unit is installed with conventional venting or sidewall venting.

CAUTION: Under no circumstances should the equipment room be under a negative pressure when atmospheric combustion equipment is installed in the room.

(FIG. 3) COMBUSTION AIR DIRECT FROM OUTSIDE

1.If air is taken directly from outside the building with no duct, provide two permanent openings:

A. Combustion air opening with a minimum free area of one square inch per 4000 Btu input (5.5 cm2 per kW).

This opening must be located within 12” (30 cm) of the bottom of the enclosure.

B.Ventilation air opening with a minimum free area of one square inch per 4000 Btu input (5.5 cm2 per kW). This opening must be located within 12” (30 cm) of the top of the enclosure.

(FIG. 4) COMBUSTION AIR THROUGH DUCTWORK

2.If combustion and ventilation air is taken from the outdoors using a duct to deliver the air to the mechanical room, each of the two openings should be sized based on a minimum free area of one square inch per 2000 Btu input (11 cm2 per kW).

(FIG. 5) COMBUSTION AIR FROM AN

INTERIOR SPACE

3.If air is taken from another interior space, each of the two openings specified above should have a net free area of one square inch for each 1000

EXAMPLE OF

SIZING FOR

COMBUSTION

&VENTILATION AIR OPENINGS (WATER HEATER WITH 2,065,000 Btu/hr INPUT):

When combustion and ventilated air is taken from directly outside the building (FIG. 4), divide the total BTU’s by 4,000. This yields 516.25 sq.in. of “Free Area” without restriction.

(2,065,000 ÷ 4000 =

516.25 sq.in.)

Since the air opening is 50% closed due to screens and louvers, the total opening must be multiplied by 2.

(516.25 sq. in. x 2 =

1,032 sq.in.)

This project requires one Ventilation Air Opening with net “Area” of 1,032 square inches with louver dimensions of 30” x 35” and one

Combustion Air Opening with net “Area” of 1,032 square inches with louver dimensions

of 30” x 35”.

L o c h i n v a r D E S I G N E R ’ S G U I D E C O P P E R - F I N W A T E R H E A T E R 6 1 5 - 8 8 9 - 8 9 0 0

5

 

 

 

 

Page 6 Page 8
Page 7
Image 7
Lochinvar CW 645, CW 745 manual Combustion & Ventilation AIR
Page 6 Page 8

CW 645, CW 745 specifications

The Lochinvar CW 645 and CW 745 are advanced water heater models from Lochinvar, a leading manufacturer of water heating solutions. These high-efficiency units are designed to meet the demands of both commercial and residential applications, combining cutting-edge technology with robust performance.

One of the defining features of the CW series is its commitment to energy efficiency. With their stainless steel construction, these water heaters boast a high thermal efficiency rating. The CW 645 and CW 745 utilize modulating technology, allowing them to adjust the heating output based on real-time demand. This results in reduced energy consumption and lower operational costs, making them an ideal choice for environmentally conscious consumers.

These models are equipped with a powerful burner system designed to provide optimal heating performance. The burners are engineered for reliability and longevity, ensuring consistent hot water supply even under heavy usage. Additionally, the CW 645 and CW 745 feature a compact footprint, making them suitable for installation in tight spaces or areas with limited access.

The advanced control system in these units takes user experience to the next level. With intuitive controls and a digital display, users can easily set temperatures and monitor system performance. The integrated diagnostics feature ensures quick troubleshooting, enhancing reliability and reducing maintenance time.

Safety is another paramount consideration in the design of the CW series. Both models come equipped with multiple safety features, including a flame safeguard system and a high-temperature limit switch. These safety mechanisms provide peace of mind while ensuring compliance with local building codes.

Furthermore, the CW 645 and CW 745 models are versatile in their applicability. They can be used for a variety of applications including restaurants, schools, and hospitals. Their ability to provide consistent hot water makes them particularly valuable in high-demand situations.

In summary, the Lochinvar CW 645 and CW 745 are exceptional water heating solutions that epitomize efficiency, safety, and performance. With advanced features, user-friendly controls, and solid construction, these units are well-suited to meet the hot water needs of both commercial and residential users. Investing in a CW series water heater not only secures a reliable source of hot water but also contributes to long-term energy savings and environmental sustainability.
Top Page Image Contents