8
Part Number 550-142-785/0812
GWI
Series 2
Gas-Fired Water Boilers –
Boiler Manual
3 Vent installation
continued
Chimney draft venting
Inspect existing chimney before installing boiler.
Failure to clean or replace perforate pipe or lining
will cause severe personal injury or death.
Vent sizing given in Figure 3 is only a general
guideline. The vent connector and chimney must
be designed, sized and constructed in compliance
with all applicable codes. Failure to correctly size
and install the vent system could result in severe
personal injury, death or substantial property dam-
age.
See
page 4
for additional requirements when chim
-
ney draft venting.
1. Use doublewall metal vent (B-vent) or chimney with liner as
required by the National Fuel Gas Code, ANSI Z223.1–latest
edition, or in Canada, B149.1 or B149.2 Installation Code.
2. To prevent downdrafts, chimney should extend at least 3 feet
above the highest point where it passes through a roof and
at least 2 feet higher than any portion of a building within a
horizontal distance of 10 feet.
3. To vent with another appliance, see National Fuel Gas Code,
ANSI Z223.1–latest edition or in Canada B149.2 or B149.2
Installation Code
4. Do not connect breeching to any portion of a mechanical draft
system that can operate under positive pressure.
5. Maintain minimum 2” clearance from combustible materials
to vent pipe.
6. Do not use chimney with an open fireplace.
7. Make horizontal runs as short as possible. Long runs can
cause condensation.
8. When longer runs are used, support pipe with appropriate
hangers.
9. To prevent blockage, do not vent into bottom of chimney.
10. Vent pipe must not go beyond inside wall of chimney.
11. Vent passing through floors or ceilings must be firestopped.
12. See Figure 3 to connect boiler to venting system.
Figure 3
Chimney draft venting installation
