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Finned copper tube gas boilers & water heaters – Boiler Manual
9
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F
SIDE WALL VENT, POSITIVE PRESSURE,
CATEGORY IV
In this confi guration the boiler/water heater blower is used to push
the fl ue products horizontally to the outdoors, see Figure 5. Th e
air for combustion is taken from the space in which the unit is
installed. Th e applicable instructions under the “COMBUSTION
AIR & VENTILATION” section must be followed! Th e vent
guidelines under the Horizontal Direct Vent Systems section must
also be followed.
VERTICAL VENT, NEGATIVE PRESSURE,
CATEGORY II
Th e Futera III is listed as a Category II appliance when vented
vertically into a listed metal chimney system, Figures 6 & 7. Th e
chimney must provide a
negative
pressure not greater than
0.15
in
,
3.8 mm
W.C. at the boiler/water heater fl ue collar with the
unit running. A barometric damper must be installed between the
fl ue collar and the vent connector when negative pressures exceed
0.15 in
,
3.8 mm
W.C.
When using a listed metal chimney system the chimney
system manufacturer’s instructions must be followed.
Masonry chimneys, when used, must be lined with a
metal liner certifi ed for Category IV venting.
When more than one appliance is connected to the same chimney
fl ue, the fl ue must be large enough to safely vent the combined
output of all of the appliances.
Figure 5
Side Wall Venting
If an appliance using any type of a mechanical draft
system operating under positive pressure is connected
to a chimney fl ue, never connect any other appliances
to this fl ue. Doing so can result in excessive levels
of carbon monoxide which can cause severe personal
injury or death!
Chimney Inspection & Sizing
A thorough inspection of the masonry chimney must be performed
to ensure that the chimney is clean, properly constructed, lined
and sized. Exterior masonry chimneys should not be used unless
properly lined to prevent condensation and draft problems. Table
5 lists the equivalent breeching and fl ue sizes required for the boiler/
water heater.
Table 5
Equivalent Breeching & Chimney Size, Negative Pressure
Model Size
Pipe Diameter
in
mm
500
6
152
750
6
152
1000
7
178
1250
8
203
1500
8
203
1750
10
254
2000
10
254
Note: These sizes are based on a 20 ft, 6.1m chimney height.
