Combustion And Ventilation Air - Lennox OHR23-105 Installation Instructions Manual

Masonry Chimney
BAROMETRIC
CONTROL*
(IN EITHER
LOCATION)
HORIZONTAL
APPLICATION
SHOWN
CLEAN OUT
*BAROMETRIC CONTROL MAY BE INSTALLED IN EITHER VERTICAL OR HORIZON-
TAL SECTION OF FLUE PIPE WITHIN 18" OF FLUE OUTLET OF FURNACE.
Figure 8
10. Extend the vent pipe into the chimney so that it is flush
with the inside of the vent liner. Seal the joint between
the pipe and the liner.
11. The furnace shall be connected to a factory built chim-
ney or vent complying with a recognized standard, or
masonry or concrete chimney lined with a lining mate-
rial acceptable to the authority having jurisdiction.
12. When two or more appliances vent into a common
vent, the area of the common vent should not be less
than the area of the largest vent or vent connection
plus 50% of the areas of the additional vent or vent
connection. Chimney must be able to sufficiently vent
all appliances operating at the same time.
13. The vent pipe shall not be connected to a chimney vent
serving a solid fuel appliance or any mechanical draft
system.
14. All unused chimney openings should be closed.
15. All vent pipe run through unconditioned areas or out-
side shall be constructed of factory built chimney sec-
tions. See figure 9.
16. Where condensation of vent gas is apparent, the vent
should be repaired or replaced. Accumulation of con-
densation in the vent is unacceptable.
17. Vent connectors serving this appliance shall not be
connected into any portion of mechanical draft sys-
tems operating under positive pressure.
18. Keep the area around the vent terminal free of snow,
ice and debris.
LINER
BAROMETRIC
CONTROL*
(IN EITHER
LOCATION)
CLEAN
HORIZONTAL
OUT APPLICATION
SHOWN
MASONRY
CHIMNEY
*BAROMETRIC CONTROL MAY BE INSTALLED IN EITHER VERTICAL OR HORI-
ZONTAL SECTION OF FLUE PIPE WITHIN 18" OF FLUE OUTLET OF FURNACE.
Combustion and Ventilation Air (Confined and
Unconfined Spaces)
Homes designed with energy conservation in mind use
air-tight construction practices. Therefore, it is necessary
to bring in outside air for combustion. Consideration must
also be given to the use of exhaust fans, appliance vents,
chimneys and fireplaces that force out air which might
have otherwise been used for combustion. Unless outside
air is brought into the home for combustion, negative pres-
sure (pressure outside is greater than inside pressure) will
build to the point that a downdraft can occur in the furnace
vent pipe or chimney. Combustion gases entering the liv-
ing space create a potentially dangerous situation.
NOTE − The importance of the previous paragraph can-
not be overstated. Users may inadvertently block fresh
air intakes after installation.
In the absence of local codes concerning air for combus-
tion and ventilation, the following section outlines guide-
lines and recommends procedures for operating oil fur-
naces in a manner that ensures efficient and safe
operation. Special consideration must be given to combus-
tion air needs as well as requirements for exhaust vents and
oil piping.
Combustion Air Requirements
All oil-fired appliances require air to be used for the com-
bustion process. If sufficient amounts of combustion air
are not available, the furnace or other appliance will oper-
ate in an inefficient and unsafe manner. Enough air must
be provided to meet the needs of all fuel-burning ap-
pliances, as well as appliances such as exhaust fans which
force air out of the home.
Page 8
Factory-Built Chimney
Figure 9
FACTORY
BUILT
CHIMNEY
DRAIN FOR
CONDENSATE