Lennox EL180UHE Installation Instructions Manual page 16

Do not install a manual damper, barometric draft regulator,
or flue restrictor between the furnace and the chimney.
Never connect a Category I appliance to a chimney that is
servicing a solid-fuel appliance. If a fireplace chimney flue
is used to vent this appliance, the fireplace opening must
be permanently sealed.
A type B or listed chimney lining system that passes
through an unused masonry chimney flue is not consid-
ered to be exposed to the outdoors.
General Venting Requirements
Vent all EL180UHE furnaces according to these instruc-
tions:
1 - Vent diameter recommendations and maximum
allowable piping runs are found in the provided
venting tables.
2 - In no case should the vent or vent connector
diameter be less than the diameter specified in the
provided venting tables.
3 - The minimum vent capacity determined by the
sizing tables must be less than the low fire input
rating and the maximum vent capacity must be
greater than the high fire input rating.
4 - Single appliance vents - If the vertical vent or tile-
lined chimney has a larger diameter or flow area than
the vent connector, use the vertical vent diameter to
determine the minimum vent capacity and the vent
connector diameter to determine the maximum vent
capacity. The flow area of the vertical vent, however,
shall not exceed 7 times the flow area of the listed
appliance categorized vent area, drafthood outlet
area or flue collar area unless designed according
to approved engineering methods.
Common Venting Using Tile-Lined Interior Masonry Chimney and Combined Vent Connector
NOTE- Refer to provided venting tables
for installations.
MINIMUM LENGTH = AS SHORT AS PRACTICAL.
FOR MAXIMUM LENGTH SEE NOTE TO LEFT
OTHER
APPLIANCE
FURNACE
AIR FLOW
Figure 24
Page 16
5 - Multiple appliance vents - The flow area of the
largest section of vertical vent or chimney shall
not exceed 7 times the smallest listed appliance
categorized vent area, drafthood outlet area or flue
collar area unless designed according to approved
engineering methods.
6 - The entire length of single wall metal vent connector
shall be readily accessible for inspection, cleaning,
and replacement.
7 - Single appliance venting configurations with zero
lateral lengths (table 3) are assumed to have
no elbows in the vent system. For all other vent
configurations, the vent system is assumed to have
two 90° elbows. For each additional 90° elbow or
equivalent (for example two 45° elbows equal one
90° elbow) beyond two, the maximum capacity
listed in the venting table should be reduced by
10% (0.90 x maximum listed capacity).
8 - The common venting tables (4 and 5) were
generated using a maximum horizontal vent
connector length of 1-1/2 feet (.46 m) for each inch
(25 mm) of connectord iameter as follows:
Connector Diameter
inches (mm)
3 (76)
4 (102)
5 (127)
6 (152)
7 (178)
VENT
CONNECTOR
TABLE 2
Maximum Horizontal
Connector Length feet (m)
4-1/2 (1.37)
6 (1.83)
7-1/2 (2.29)
9 (2.74)
10-1/2 (3.20)
INTERIOR TILE-LINED
MASONRY CHIMNEY
NOTE - the chimney must be properly
sized per provided venting tables or
lined with listed metal lining system.
PERMANENTLY
SEALED FIREPLACE
OPENING