Weil-McLain GOLD CGS 550-110-260/02002 - Manual (Page 10)

Part number 550-110-260/0200
10
GOLD CGs Gas-Fired Water Boiler
Prepare boiler location — air openings
1e
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 if appliances are to use
inside air for combustion and ventilation.
Exhaust fans and air movers
The appliance space must never be under a negative
pressure unless all appliances 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 isolated contact
(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.
CGs combustion air options
Using inside air — direct exhaust vent
The CGs boiler can use inside air if no contaminants
are present in the boiler space. If contaminants are likely
to be present, install the CGs boiler as a direct vent
appliance, using the appropriate vent supplement and
the instructions in this manual.
Using outside air — direct vent
Combustion air can be ducted directly from outside
to the CGs boiler air intake fitting. This method is
defined as
direct vent (also referred to as sealed
combustion). Refer to the appropriate vent supplement
and the instructions in this manual. Two options are
available: sidewall or vertical direct vent. Each requires
a special vent component kit.
Sizing air openings
Air openings provide for ventilation (as well as
combustion air) to prevent overheating of the boiler
controls and boiler space. Air is also needed for other
appliances located in the same space.
Use Figure 3 , selecting the appropriate installation
conditions. Note that the sizing given in Figure 3
applies only to CGs installations with
clearances no
smaller than shown in Figure 1, page 7 of this manual.
For smaller clearances, regardless of how the air
openings are arranged, two openings providing free
area of 1 square inch per 1,000 Btuh input of all
appliances in the space are required.
Air openings must be sized to
handle all appliances and air
movers (exhaust fans, etc.) using the
air supply.
The sizing given in Figure 3 is based on the National
Fuel Gas Code, ANSI Z223.1, allowing adequate air
opening for gravity-vented gas appliances (Category I).
The CGs boiler is rated Category III or IV (pressurized
vent), and has different requirements for combustion
and ventilation air, reflected by the special sizing
instructions given in Figure 3. The air openings
recommended in Figure 3 will allow adequate
ventilation and combustion air provided the boiler
room is not subjected to negative pressure due to
exhaust fans or other mechanical ventilation devices.
Refer to the National Fuel Gas Code for dealing with
other conditions.
Louver allowance
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 openings.