9
MASONARY THIMBLE
3" CLEARANCE TO
COMBUSTIBLE
24"
PL VENT TEE
WITH CLEANOUT
CAP
STORM
COLLAR
ALWAYS FOLLOW PL VENT
MANUFACTURERS CLEARANCES
TO COMBUSTIBLES
FLASHING
CEILING OR
WALL THIMBLE
3" CLEARANCE TO
COMBUSTIBLE
PL VENT TEE
WITH CLEANOUT
Venting into an Existing chimney
combustion air
1. If the furnace’s exhaust is connected to a masonry chimney,
the masonry chimney must be free of cracks that could leak
exhaust gases or fly ash. a relining of the chimney with ei-
ther PL vent or single wall stainless steel pipe may be neces-
sary to bring the chimney into compliance.
2. When chimneys are relined, a chimney chase cap that
reduces the outlet of the chimney to the size of the liner is
required. Extend the exhaust vent above the chimney chase
cap and finish it off with a rain cap. a single wall liner may
need to be wrapped with insulation to maintain adequate
exhaust temperatures when outside temperatures drop be-
low freezing, causing the flue temperatures to become too
low.
3. Venting into the side of an existing masonry chimney must
be done through a masonry thimble. When wall penetration
is necessary to access a masonry chimney, use a listed PL
vent wall thimble. chimney connectors should be made with
minimum 24 Gauge black or blue steel.
4. When venting into a Class A steel chimney, use an appro
-
priate PL Vent adapter.
The 50F furnace may be connected to an existing class a chimney or a masonry chimney which meets the
minimum requirements of nFPa 211.
• Outside air is required.
• Outside air may be drawn from a semi-enclosed attic or
crawl space or any semi-enclosed space. Take care not to
draw cold air past water pipes that may freeze.
• Use 3" or greater flexible or rigid metal piping.
• Terminate the outside air pipe below the exhaust vent outlet.
• An open mesh screen should be placed over the outside air
pipe opening to prevent birds or rodents from nesting in the
opening. Use an elbow or shield to prevent prevailing winds
from blowing directly into the outside air intake pipe. NOTE:
Mesh screen should be no smaller than one-fourth inch
(1/4") by one-fourth inch (1/4").
Figure 6
EndURancE 50F
vENTING INTO AN EXISTING ChIMNEY
NOTE: The outside air pipe must terminate above the
maximum snow line. Long runs should be avoided.
WARNING
Outside combustion air is required for
all installations!
WARNING
Use the air intake damper for adjusting combustion inlet air only! Other methods of restricting or blocking
combustion inlet air are strictly prohibited!
Figure 7
Air Intake
Damper
