Boiler Manual - Weil-McLain

GV90+ gas-fired water boiler — Boiler ManualDIRECT VENT — Boiler room air openingsFigure 42 Combustion and ventilation air openings for GV90+ Direct Vent installationsThe GV90+ boiler CANNOT be in the same space with other appliances if clearances around the GV90+ are less thanthe recommended service clearances shown in Figure 2, page 6.Air openingsThe required air opening sizes below are FREE AREA,after reduction for louver obstruction. Note the exceptionbelow for large spaces.GV90+ boilerWITH otherappliances in roomGV90+ boilerWITHOUT otherappliances in roomTWO openings, each at least:1 square inch per 1,000 Btuhof all other appliances in the roomTWO openings, each at least:1 square inch per 4,000 Btuhof all other appliances in the room— OR —ONE opening **, each at least:1 square inch per 3,000 Btuhof all other appliances in the roomTWO openings, each at least:1 square inch per 2,000 Btuhof all other appliances in the room— OR —ONE opening **, each at least:1 square inch per 3,000 Btuhof all other appliances in the roomNO openings are required if theboiler installation provides at least therecommended service clearancesshown in Figure 2, page 6.If the space is smaller than Figure2, page 6, provide openingsONLY as shown on page 7 andFigure 4, page 7.TWO openings, each at least:1 square inch per 4,000 Btuhof all other appliances in the room— OR —ONE opening **, each at least:1 square inch per 3,000 Btuhof all other appliances in the room** NOTICE:Requirements for using the SINGLE air openingoption.SPECIAL EXCEPTION FOR LARGE SPACES(GV90+ WITH other appliances in room only):A single combustion air opening can be used for cases b, c or d above (GV90+ withother appliances in room only), sized as listed, provided that:• The single opening must communicate directly to the outdoors or to a space thatcommunicates directly with outdoors (NOT to an interior space).• The top of the opening must be within 12 inches of the ceiling.• The free area of the opening must be at least equal to the sum of the areas of allequipment vent connectors in the space.NO combustion air openings are needed when the boiler (and other appliances) areinstalled in a space with a volume NO LESS than 50 cubic feet per 1,000 Btuh of all appliancesin the space. That is, total the input of all appliances in MBH (1,000’s of Btuh),then multiply this total times 50. The building MUST NOT be of tight construction.Example: For a total input of 500 MBH (500,000 Btuh), the minimum volume would be50 x 500 = 25,000 cubic feet (3,125 square feet if ceiling height is 8 feet).36Part number 550-142-054/1211