Lanair MXB360 User Manual
Page 9
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9
Section 3 - Boiler Room Air Requirements
Figure 2
When air comes directly from outdoors, again use two openings as explained on page 8 and above except:
• Direct connection or vertical ducting allow 1 sq. inch per 4,000 BTU/HR.
• Direct connection through horizontal ducting allow 1 sq. inch per 2,000 BTU/HR
• All ducting shall be the same size as opening but no less than 3" x 3" or 9 square inches.
Remember to compensate for louver blockage when calculating free air. Refer to manufacturer's instructions or use this
general guide:
WOOD LOUVERS- Allow 20-25% free air
METAL LOUVERS OR GRILLES - Allow 60-70% free air
Any louver damper should lock open or interlock with the burner to open automatically when the boiler operates.
12" Maximum
Louvered
openings for
ventilation &
combustion
12" Maximum