Minimum Vent Pipe Clearance - Dunkirk XEB-2 Installation Manual

tables in the National Fuel Gas Code or the
Canadian Installation Codes, and may be
required to be larger than 4" diameter.
The boiler installation for chimney venting
is not complete unless the 3" x 4" increaser
fitting is located and secured.
3. These are high efficiency boilers with a low
stack or exhaust temperature.
4. If venting into a masonry chimney without a
liner, line the chimney from top to bottom with
either:
a. listed Type B vent pipe
b. listed flexible vent liner
c. poured ceramic liner.
5. Outside chimneys should not be used unless
they are either:
a. enclosed in a chase, or
b. Iined with Type B vent pipe, or listed flexible
vent liner, or other certified chimney lining
system.
6. The vent connector from the boiler to the
chimney should run as directly as possible
with as few elbows as possible.
7. Where possible, it is recommended to common
vent the water heater and boiler. Consult the
appropriate Vent Sizing Tables in either the
National Fuel Gas Code, or the Canadian
Installation Codes for specific requirem ents
of multiple appliance venting.
8. If the boiler is the only appliance connected
to the vent, Type B vent pipe is recommended
for the vent connector.
9. Slope pipe up from boiler to chimney not
less than 1/4" per foot.
10. End of vent pipe must be flush with the inside
face of the chimney flue. Use a sealed-in
thimble for the chimney connection.
ChImNeY ANd VeNt pIpe CoNNeCtIoN
11. The sections of vent pipe should be fastened
with sheet metal screws to make the piping
rigid. Use stovepipe wires to support the pipe
from above.
12. Do not connect to fireplace flue.
13. Do not install a damper on this boiler.

MINIMUM VENT PIPE CLEARANCE

If the vent pipe must go through a crawl space,
Type B vent pipe should be used. Where vent
pipe passes through a combustible wall or
partition, use a ventilated metal thimble. The
thimble should be 4 inches larger in diameter
than the vent pipe.
If boiler is installed with single wall vent, it must
have a 6" clearance between its surface and any
combustible material. A new Type B gas vent or
flexible liner must be installed in accordance with
the instructions furnished with the vent. Maintain
clearances as specified for the vent pipe.
Check the vent pipe to see if it is fire-stopped
where it goes through the floor or ceiling. It should
have an approved vent cap with clearances from
the roof as shown in Figure #8. If clearances are
less than shown in Figure #8, have the vent
checked by local authorities.
For boilers for connection to gas vents or
chimneys, vent installations shall be in
accordance with the National Fuel Gas Code,
ANSI Z223.1-latest revision and applicable
provisions of the local building codes. In
Canada, follow CSA B149.1 or .2 Installation
Codes.
Vent connectors serving appliances vented by
natural draft shall not be connected into any
portion of mechanical draft systems operating
under positive pressure.
10