Lochinvar SNA285-125, SNA500-125 1Determine water heater location, Installation & Service Manual

TM

Installation & Service Manual

1Determine water heater location

Figure 1-3_Combustion Air Direct from Outside

1.If air is taken directly from outside the building with no duct, provide two permanent openings to the equipment room (see FIG. 1-3):

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

Figure 1-4_Combustion Air Through Ducts

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2.If combustion and ventilation air is taken from the outdoors using a duct to deliver the air to the equipment room, each of the two openings should be sized based on a minimum free area of one square inch per 2000 Btu/hr (11 cm2 per kW) of input (see FIG. 1-4).

IF NECESSARY FOR

TIGHT CONSTRUCTION

Figure 1-5_Combustion Air from 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 Btu/hr (22 cm2 per kW) of input, but not less than 100 square inches (645 cm2) (see FIG. 1-5).

Figure 1-6_Combustion Air from Outside - Single Opening

4.If a single combustion air opening is provided to bring combustion air in directly from the outdoors, the opening must be sized based on a minimum free area of one square inch per 3000 Btu/hr (7 cm2 per kW). This opening must be located within 12" (30 cm) of the top of the enclosure (see FIG. 1-6).