Room Air Openings; Combustion Air Provision; Sizing Combustion Air Openings; Special Considerations - Weil-McLain 4 Series Manual

sTeam series
94

Room Air Openings

Combustion Air Provision

The 94 commercial boiler can use inside air if no
contaminants are present in the boiler space If
contaminants are likely to be present, install the
boiler as a direct vent appliance Use the appropriate
vent instructions in this manual
The boiler room must be fitted with combustion
air openings large enough to provide air for all
appliances in the room Use the following information
to size the openings Ensure the installation complies
with all applicable codes and standards

Sizing Combustion Air Openings

Air openings provide ventilation to prevent
overheating of the boiler controls and boiler space
Air is also needed for other appliances located in the
same space Use the information in Figure 33, page
42 for air openings
WARNING
!
Air openings must be sized to handle all
appliances and air movers, such as exhaust fans,
using the air supply. Failure to comply can result
in severe personal injury, death, or substantial
property damage.
The sizing given in Figure 33, page 42 is based
on the National Fuel Gas Code – ANSI Z223 1/
NFPA 54, latest edition The sizing allows adequate
air openings for gravity-vented gas appliances
(Category I), in addition to the needs for the 94 boiler,
provided the boiler room is not subjected to negative
pressure due to exhaust fans or other mechanical
ventilation devices
The 94 commercial boiler has varying
requirements for combustion and ventilation air,
reflected by the special sizing instructions given in
this manual Refer to the National Fuel Gas Code for
dealing with other conditions
Free area and louvers
The free area of openings means the area after
reduction for any installed louvers or grilles Be
sure to consider this reduction when sizing the air
opening
550-100-157/0523
boiler manual
4

Special Considerations

Tight construction
The National Fuel Gas Code – ANSI Z223 1/NFPA
54, latest edition defines unusually tight construction
where all of the following is true:
1 Walls and ceilings exposed to the outside
atmosphere have a continuous water vapor
retarder with a rating of 1 perm or less with
openings fitted with gaskets.
2 Weather-stripping has been added on windows
and doors that are capable of being opened
3 Caulking or sealants are applied to areas such as
joints around windows and door frames, between
sole plates and floors, between wall-ceiling
joints, between wall panels, at penetrations for
plumbing, electrical, and gas lines, and in other
openings
For buildings with such construction, provide air
openings into the building from outside Size the
openings per the appropriate condition in Figure
33, page 42 if appliances are to use inside air for
combustion and ventilation
Exhaust fans and movers
The appliance space must never be under a
negative pressure Always provide air openings
sized to the dimensions required for the firing rate
of all appliances, with the ability to handle the air
movement rate of the exhaust fans or air movers
using air from the building or space
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