Weil-McLain GOLD CGa Installation And Maintenance Manual page 11

Boiler Manual
Figure 4 Air from outdoors — vertical ducts
Outside or ventilated attic
Each opening free area =
1 sq. inch per 4,000 Btuh
Other
appliances
MODEL MODEL
CGi CGi
Ventilated
crawl space
59321c
4. When combustion air is supplied to the boiler space
directly from outside through horizontal ducts
: Provide two permanent openings:
(Figure 5)
• One air opening within 12 inches of floor.
• A second opening within 12 inches of ceiling.
Each opening must provide a minimum free area
of
1 square inch per 2,000 Btuh of input
appliances in room plus requirements for any
exhaust fans in room. The duct cross sectional area
must be no less than the required area of the
permanent openings.
Figure 5 Air from outdoors — horizontal ducts
Each opening free area =
1 sq. inch per 2,000 Btuh
Other
appliances
CGi CGi MODEL MODEL
59321d
Part Number 550-110-593/1099
CGa
boiler
— or —
12"
of all
0 to 12"
CGa
boiler
0 to 12"
Special considerations
Tight construction
ANSI Z223.1 defines unusually tight construction
where:
a. Walls and ceilings exposed to the outside
atmosphere have a continuous water vapor retarder
with a rating of 1 perm or less with openings
gasketed, and . . .
b. Weather-stripping has been added on openable
windows and doors, and . . .
c. 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, sized per the
appropriate case in
Figure 3
inside air for combustion and ventilation.
Exhaust fans and air movers
The appliance space must never be under a negative
pressure, even if the appliance(s) are installed as direct
vent. Always provide air openings sized not only to the
dimensions required for the firing rate of all appliances,
but also to handle the air movement rate of the exhaust
fans or air movers using air from the building or space.
Motorized air dampers
If the air openings are fitted with motorized dampers,
electrically interlock the damper to:
• Prevent the boiler from firing if the damper is not
fully open.
• Shut the boiler down should the damper close
during boiler operation.
To accomplish this interlock, wire an
(proving the damper open) in series with the thermostat
input to the boiler. The boiler will not start if this contact
is open, and will shut down should it open during
operation.
if appliances are to use
isolated contact
11