Weil-McLain 550-110-260/02002 manual Sizing air openings for CGs installations

Boiler Manual

Figure 3 Sizing air openings for CGs installations

Room Air Openings

Required area of the air openings given in this table are free area — after the correction for louver obstruction. (See Exception below.)

Apply this table only to installations with clearances no smaller than those shown in Figure 1, page 7 of this manual.

For installations with clearances less than shown in Figure 1, page 7 of this manual, provide 2 openings, each with 1 square inch of free area per 1,000 Btuh of total input of all appliances.

Direct exhaust vent installation	Direct vent installation
(CGs using room air for combustion)	(combustion air piped to CGs)
	Combustion	Combustion
	air piping	air piping
Other	Other
appliances	appliances

CGs CGs CGs CGs

Room shared	CGs alone	Room shared	CGs alone
with other appliances	in room	with other appliances	in room
2 Openings —	2 Openings —	2 Openings —	NO Openings are
each opening:	each opening:	each opening:	needed, provided:

A Air from Inside	12”
	Max

CGs

12”

Max

Air

opening

Inside Outside

Air

opening

1 square inch	1 square inch	1 square inch
free area per	free area per	free area per	Clearance around
1,000 Btuh input of	4,000 Btuh input	1,000 Btuh input of	boiler is NO LESS
			than shown in
other appliances	of CGs	other appliances
			Figure 1, page 7
plus CGs		only (not CGs)
			of this manual.
2 Openings —	2 Openings —	2 Openings —	NO Openings are

BAir Directly from Outside

CGs

12”

Max

Air

opening

Outside

Air

opening

12”

Max

each opening:	each opening:	each opening:	needed, provided:
1 square inch	1 square inch	1 square inch
free area per	free area per	free area per	Clearance around
4,000 Btuh input of	4,000 Btuh input	4,000 Btuh input of	boiler is NO LESS
			than shown in
other appliances	of CGs	other appliances
			Figure 1, page 7
plus CGs		only (not CGs)
			of this manual.
2 Openings —	2 Openings —	2 Openings —	NO Openings are
each opening:	each opening:	each opening:	needed, provided:

C Air from Outside	12”
	Max
Through horizontal	Air
ducts
	opening

Duct
Inside	Outside

1 square inch	1 square inch	1 square inch
free area per	free area per	free area per	Clearance around
2,000 Btuh input of	4,000 Btuh input	2,000 Btuh input of	boiler is NO LESS

CGs

Air

opening

12”

Max

Duct

other appliances	of CGs	other appliances	than shown in
			Figure 1, page 7
plus CGs		only (not CGs)
			of this manual.

Outside or ventilated attic

DAir from Outside or Attic — Lower Opening in Floor

or Vertical Duct		Duct	Outside
CGs	12”
	Max	Or
Ventilated
crawl space
26007

2 Openings —	2 Openings —	2 Openings —	NO Openings are
each opening:	each opening:	each opening:	needed, provided:
1 square inch	1 square inch	1 square inch
free area per	free area per	free area per	Clearance around
4,000 Btuh input of	4,000 Btuh input	4,000 Btuh input of	boiler is NO LESS
			than shown in
other appliances	of CGs	other appliances
			Figure 1, page 7
plus CGs		only (not CGs)
			of this manual.

Exception to combustion air opening rules:

NO combustion air openings are needed when the boiler (and other appliances) are installed in a space with a volume NO LESS than 50 cubic feet per 1,000 Btuh of all installed appliances. Sum the total input of all appliances in MBH (1,000's of Btuh) and multiply this number times 50. Building must not be of Tight construction (see page 10).

Example: For total input of 100 MBH (100,000 Btuh), minimum volume is 50 x 100 = 5,000 cubic feet. At a ceiling height of 8 feet, space must have at least 5,000 ÷ 8 = 625 square feet (25 feet x 25 feet, for instance).

Part number 550-110-260/0200 11