18-CD34D1-5-EN 13
INSTALLER’S GUIDE
VENTING INTO A MASONRY CHIMNEY
If the chimney is oversized, the liner is inadequate, or flue-
gas condensation is a problem in your area, consider using the
chimney as a pathway or chase for type “B” vent or flexible vent
liner. If flexible liner material is used, size the vent using the “B”
vent tables, then reduce the maximum capacity by 20% (multiply
0.80 times the maximum capacity).
Internal Masonry Chimneys
Venting of fan assisted appliances into a lined, internal masonry
chimney is allowed only if it is common vented with at least one
natural draft appliance; OR, if the chimney is lined with type “B”,
double wall vent or suitable flexible liner material (See Table 7).
▲
WARNING
!
The chimney liner must be thoroughly inspected
to insure no cracks or other potential areas for
flue gas leaks are present in the liner. Liner leaks
will result in early deterioration of the chimney.
Failure to follow this warning could result in
carbon monoxide poisoning or death.
TABLE 7
MASONRY CHIMNEY VENTING
Tile Lined Chimney
Chimney Lining
Type Furnace
Internal
External
“B” Vent
Flexible
Metal Liner
Single Fan
Assist
No
No
Yes
Yes*
Fan Assist
+ Fan Assist
No
No
Yes
Yes*
Fan Assist
+ Natural
Yes
No
Yes
Yes*
* Flexible chimney liner size is determined by using the type “B” vent size
for the available BTUH input, then reducing the maximum capacity by 20%
(multiply maximum capacity times 0.80). The minimum capacity is the same
as shown in the “B” vent tables.
External Masonry Chimney
▲
WARNING
!
CARBON MONOXIDE POISONING HAZARD
This masonry chimney kit shall NOT be installed
on any furnaces with 40,000 BTU/H inputs or any
downflow models. Failure to follow this warning
could result in carbon monoxide poisoning,
personal injury, or death.
NOTE: Masonry Chimney Kit BAYVENT800B may be used
with these furnaces (Upflow model furnaces 60,000 BTU/H
and above only) to allow venting into an external masonry
chimney. Refer to BAYVENT800B Installer's Guide for
application requirements. The following section does not
apply if BAYVENT800B (Masonry Chimney Kit) is used. All
instructions with the kit must be followed.
▲
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below for
each appliance connected to the venting system
being placed into operation could result in carbon
monoxide poisoning or death.
The following steps shall be followed for each appliance
connected to the venting system being placed into
operation, while all other appliances connected to the
venting system are not in operation:
1. Seal any unused openings in the venting system.
2. Inspect the venting system for proper size and
horizontal pitch, as required in the National Fuel Gas
Code, ANSI Z223.1/NFPA 54 or the CAN/CGA B149
Installation Codes and these instructions. Determine
that there is no blockage or restriction, leakage,
corrosion and other deficiencies which could cause
an unsafe condition.
3. As far as practical, close all building doors and
windows and all doors between the space in which
the appliance(s) connected to the venting system are
located and other spaces of the building.
4. Close fireplace dampers.
5. Turn on clothes dryers and any appliance not
connected to the venting system. Turn on any exhaust
fans, such as range hoods and bathroom exhausts,
so they are operating at maximum speed. Do not
operate a summer exhaust fan.
6. Follow the lighting instructions. Place the appliance
being inspected into operation. Adjust the thermostat
so appliance is operating continuously.
7. If improper venting is observed during any of the
above tests, the venting system must be corrected
in accordance with the National Fuel Gas Code,
ANSI Z221.1/NFPA 54 and/or CAN/CGA B149
Installation Codes.
8. After it has been determined that each appliance
connected to the venting system properly vents where
tested as outlined above, return doors, windows,
exhaust fans, fireplace dampers and any other gas-
fired burning appliance to their previous conditions of
use.
The furnace shall be connected to a factory built chimney or
vent complying with a recognized standard, or a masonry or
concrete chimney lined with a lining material acceptable to
the authority having jurisdiction.
▲
WARNING
!
Furnace venting into an unlined masonry chimney
or concrete chimney is prohibited.
Failure to follow this warning could result in
property damage, personal injury, or death.
