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Finned copper tube gas boilers & water heaters – Boiler Manual
9
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GENERAL VENTING GUIDELINES
The vent installation must be in accordance with Part
7, Venting of Equipment, of the National Fuel Gas
Code, ANSI Z223.1/NFPA 54-latest revision or
applicable provisions of the local building codes.
Canadian installations must comply with CSA B149.1
or .2 Installation Code. Improper venting can result in
excessive levels of carbon monoxide which can result
in severe personal injury or death!
All vent systems must be fully supported by the building structure
and not by the boiler/water heater. Appropriate thimbles and fire-
stops must be used where required.
Common vent systems must be properly engineered
and sized to provide a negative draft of .01 to 0.08 in,
.25 to 2.0 mm W.C. at the flue outlet! Common positive
pressure vent systems are not to be used. Improper
installation can result in excessive levels of carbon
monoxide which can cause severe personal injury or
death!
A single acting barometric damper must be installed
directly to the boiler/water heater flue outlet to ensure
proper operation. This does not apply to outdoor units
or direct vent positive pressure units.
Some venting applications may require the stop to
be removed for smooth operation. The barometric
damper should be located after the flue collector, refer
to Figures 2, 3 and 7 for proper location. Be sure that
the damper is mounted horizontally (never vertically).
Carefully follow the instructions provided with the
barometric damper. Check with local codes for specific
requirements.
In Canada, B149 (7.25 Draft Regulators) states the
damper shall be of double-acting type.
To avoid spillage into the room of dangerous flue gas
containing carbon monoxide, the opening in damper
must never face against the flow of flue gas.
VENT SYSTEM OPTIONS
The Dominator may be vented the following ways:
1)
Vertical/Chimney Venting, Negative Pressure, Category
I -
uses an approved metal chimney system or properly lined
masonry chimney. Combustion air is obtained from the space
in which the unit is installed or from the outdoors. A barometric
damper must be installed near the flue outlet when venting
vertically. See Figures 6 and 7. This also applies to any fan-assisted
chimneys or vents.
2)
Direct Vent, Positive Pressure, Category III -
for horizontal
vent runs equivalent to 35 ft, 10.7 m or less. A stainless steel vent
system certified to UL 1738 for installations in the United States,
ULS636 for installations in Canada must be used when
combustion air is ducted from outdoors, from the same wall.
3)
Horizontal Vent, Negative Pressure, Category I -
for
horizontal vent runs equivalent to more than
35 ft
,
10.7 m
(90
degree elbow equals 10 equivalent feet). A dedicated wall
mounted power venter and barometric damper must be used.
The vent system can be single wall galvanized steel or type B vent
pipe. Combustion air is obtained from the space in which the unit
is installed or from the outdoors.
A barometric damper must be installed when the horizontal run
is longer than 35 equivalent feet. (90 degree elbow = 10 equivalent
feet). If this is the case, a power venter must also be used.
If horizontal run is less than 35 equivalent feet, do not use a
barometric damper. Follow applicable instructions under the
"COMBUSTION AIR & VENTILATION" section.
4) Outdoor Installation - uses the outdoor option kit. Barometric
damper is not required.
All venting, combusiton air material supplied by
installer. All venting material must be approved for
the application. Consult the vent manufacturer’s
product literature.
