11
must be lined with B vent or a listed insulated flexible metal
vent. Insulation for the flexible vent pipe must be an encap
-
sulated fiberglass sleeve recommended by the flexible vent
pipe manufacturer. Insulation will need to be added to the
flexible liner if:
• It is required by the liner manufacturer’s Instructions.
• The previous liner was properly sized and installed,
and suffered from condensation damage.
A listed uninsulated flexible metal vent liner may be used in
an exterior tile lined chimney that is sealed and capped.
Poured insulation, vermiculite or other materials shall not be
used.
For sizing of flexible liners, see the tables in the National
Fuel Gas Code NFPA 54/ANSI Z223.1 - latest edition and
in the National Standard of Canada, CAN/CSA B149.1 and
CAN/CSA B149.2 – latest editions and amendments.
If a B vent liner is to be used, it must be supported adequate
-
ly. Supports (such as fire stops or thimbles) must be used
to prevent the B vent from coming into direct contact with
the tile liner or chimney walls. Direct contact would result in
higher heat loss, with an increased possibility of poor venting
system performance.
It is not acceptable to vent one appliance inside the B vent
and other appliances outside. The excess space between the
B vent and the chimney walls must be covered at the top of
the chimney by a weatherproof, corrosion resistant flashing.
The B vent shall then be topped with a listed vent cap.
WARNING
Possibility of property damage, personal injury or death
damaging condensation can occur inside masonry chimneys
when a single fan-assisted Category I appliance (80% AFUE
Furnace) is vented without adequate dilution air. Do not
connect an 80% furnace to a masonry chimney unless the
furnace is common vented with a draft hood equipped
appliance or the chimney is lined with a metal liner or Type
B metal vent. All installations using masonry chimneys
must be sized in accordance with the appropriate venting
tables. If an 80% furnace is common vented with a draft hood
equipped appliance, the potential for condensation damage
may still exist with the extremely cold conditions, long vent
connectors, exterior chimneys, or any combination of these
conditions. The risk of condensation damage is best avoided
by using masonry chimney as a pathway for properly sized
metal liner or Type B metal vent.
7. Remove the chimney transition bottom from the transi-
tion bottom kit.
8. Install the chimney top with the four screws retained
from step 6 onto the new chimney transition bottom
from the transition bottom kit.
9. Remove the induced draft blower and install the new
chimney assembly to it using the three screws retained
from step 5.
10. Rotate the induced draft blower 90 degrees to the
right, feed the flue pipe through the round cutout from
the outside of the wrapper, and fit onto the chimney
top assembly. Secure the pipe to the chimney top
from the front, top, and bottom using (3) screws and
rotating the induced draft blower to properly orient the
assembly.
NOTE:
If the pipe section is less than 18”,
then attach it directly to the chimney top on 3 sides
and feed it through the round cutout from the inside of
the wrapper.
11. Reattach the induced draft blower using the (4) screws
retained from step 3. Ensure the gasket located
between the induced draft blower and collector box is
rotated accordingly.
12. Reconnect the induced draft blower power leads.
13.
Reconnect the remaining flue pipe, and the pressure
switch tubing. Ensure that all wires and the pressure
switch tubing is at least one inch from the flue pipe, or
any other hot surface.
14. Restore power to furnace.
NOTE:
In a horizontal installation the air conditioning
coil must be adequately supported by proper brackets
and supports. Inadequate coil support can result in
furnace cabinet distortion and air leakage.
Counterflow units
are shipped with the induced draft blow-
er discharging from the top of the furnace. (“Top” as viewed
for a counterflow installation.)
Vent the furnace in accordance with the National Fuel Gas
Code NFPA54/ANSI Z223.1-latest edition.
WARNING
Never allow the products of combustion, including carbon
monoxide, to enter the return ductwork or circulation air
supply.
MASONRY CHIMNEYS
An exterior masonry chimney is defined as a “Masonry”
chimney exposed to the outdoors on one or more sides be-
low the roof line.
Masonry chimneys used to vent Category I central furnac-
es must be either tile-lined or lined with a listed metal liner
listed for venting a Category 1 appliance. Unlined masonry
chimneys are prohibited and must not be used to vent this
appliance. An exterior masonry chimney that is not tile-lined
