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Part Number 550-142-320/0720
GWA
Series 3
Gas-Fired Water Boilers –
Boiler Manual
Exhaust fans and air movers
The appliance space must never be under a negative pressure.
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, electri-
cally 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.
1 Prepare boiler location
continued
Air openings
Combustion air and ventilation openings must comply with
Section 5.3, “Air for Combustion and Ventilation”, of National
Fuel Gas Code ANSI Z223.1 – latest edition, or applicable local
building codes.
See Table 2 for minimum combustion/ventilation air opening
sizes. Where openings are required, provide two (2) openings
— one within 12 inches of the ceiling, the other within 12 inches
of the floor, as shown in the table illustrations.
Provide adequate combustion and ventilation air
to assure proper combustion and reduce the risk
of severe personal injury, death or substantial
property damage caused by flue gas spillage and
carbon monoxide emissions.
