Bard Bayrd Furnace 403293A - Manual (Page 17)

OT evidence of condensate exists, consider using
chimney as a pathway for suitably sized Type B1
vent liner. See Figure 15.
FIGURE 15
WARNIN9I Support Type B1 vent liner in ma­
sonry chimney. Maintain at least a 1" clearance
on all sides to reduce possibility of condensate
in vent. Condensate may cause vent to deterio­
rate allowing combustion products to collect In
structure, which could result In injury or death.
See Figure 16.
NOTE; For more information on proper chimney in­
spection and relining procedures, Gas Research In­
stitute (GRI) has a topical report entitled "Masonry
Chimney Inspection and Reiintng". Obtain copies
through American Gas Association (A.G.A.) at
1-800-841-8400.
6. Vent termination.
a. Terminate ail verticai vents with a iisted vent
cap or roof assembly unless local codes require
otherwise. See vent cap or roof assembly
manufacturer's instructions. Locate vent termi­
nation (vent cap or roof assembly) in an area
without positive wind pressures or eddy currents.
Eddy currents occur when air swirls over roof
peaks. They can cause down-drafts and ad­
versely affect vent operation. See Figure 17.
FIGURE 16
Some vent terminations or caps protect against
eddy currents and down-drafts, Consult their
manufacturer's instructions. Vent terminations or
caps should usually be at least the same size as
the vent. They may be larger if the installation
warrants.
b. Vent systems must end at least five feet above
the highest gas appliance connection. Vent pipe
must extend at least three feet above the point
where it passes through the roof. Vent termina­
tion must be at least two feet higher than any
portion of building within ten feet horizontal and
vent termination must be at least two feet higher
than roof peaks within ten feet horizontal. See
Figures 18 and 19. Some vent cap manufactur­
ers offer vent caps that allow reduced clearances.
Consult their Instructions.
WAKNINOi Vent liner muet not block opening
where other epplicncee' vent connector* enter
chimney. Blocked opening* could cau»* com­
bustion products to collact In atructur*, r*sutt-
Ing In damag*, Injury or dssth.
WARNINOt Do not uaa unllnad masonry chlm-
naya. Thasa Incraasa risk of condansats forma­
tion, which may causa chlmnay to datariorata,
allowing combustion products to collact In
structura, raaulting In damaga. Injury or death.
15