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Requirements
Installation of Lennox oil-fired furnaces must conform with
the National Fire Protection Association Standard for the
Installation of Oil Burning Equipment, NFPA No. 31, the
National Electrical Code, ANSI/NFPA No.70 (in the
U.S.A.), CSA Standard CAN/CSA-B139 (in Canada),
Installation Code for Oil Burning Equipment, the Canadian
Electrical Code Part1, CSA 22.1 (Canada), the recom
mendations of the National Environmental Systems Con
tractors Association and any state or provincial laws or lo
cal ordinances. Authorities having jurisdiction should be
consulted before installation. Such applicable regulations
or requirements take precedence over general instruc
tions in this manual.
Chimneys and chimney connectors must be of the type
and construction outlined in section 160 of NFPA No. 31.
Air for combustion and ventilation must conform to stan
dards outlined in section 140 of NFPA No. 31 or, in Cana
da, CSA Standard B139. When installing SLO185UFV
units in confined spaces such as utility rooms, two com
bustion air openings are required. Dimensions of combus
tion air openings are shown in table 1. One opening shall
be below burner level and the other opening shall be no
more than 6” (152 mm) from the room's ceiling.
The combustion air opening should provide a minimum free
area one‐half square inch per 1,000 Btu per hour input. This
combustion air should be brought into the area containing the
furnace below the level of the furnace burner.
IMPORTANT
An opening to the outside for combustion air is
strongly recommended, especially in new homes.
Refer to table 1 or the unit rating plate for specific
combustion air opening dimensions.
Table 1
Combustion Air Opening Dimensions
Model No.
(2 openings required)
SLO185UFV-79/105
10” X 20” (254 mm X 508 mm)
SLO185UFV-124/141 11” X 22” (279 mm X 559 mm)
This unit is approved for use on combustible flooring and for
clearances to combustible material as listed on unit rating
plate and in table 2. Unit service and accessibility clearances
take precedence over fire protection clearances.
Table 2
SLO185UFV Installation Clearances
Clearances
inches (mm)
top of plenum & duct
2 (51)
plenum sides
3 (76)
sides
0 (0)
rear
0 (0)
front
4 (120)
flue pipe
6 (152)
NOTE - When service clearances are greater than fire
protection clearances, service clearances take prece
dence.
Obtain a temperature rise within the range listed in table 8
in the Start‐Up section of this manual.
When installed, furnace must be electrically grounded in
accordance with local codes or, in the absence of local
codes, with the current National Electric Code, ANSI/
NFPA No. 70, or Canadian Electric Code (CEC) if an exter
nal electrical source is utilized.
Field wiring connection with unit must meet or exceed
specifications of type T wire and withstand a 63
_
F (17
_
C)
temperature rise.
If installing a programmable thermostat, use a type which
retains its memory in event of a power loss. When the fur
nace is used in conjunction with cooling units, it shall be
installed in parallel with, or on the upstream side of, cooling
units to avoid condensation in the heating element. With a
parallel flow arrangement, a damper (or other means to con
trol the flow of air) shall be adequate to prevent chilled air
from entering the furnace and, if manually operated, must be
equipped with means to prevent operation of either unit, un
less damper is in the full “heat” or “cool” position.
WARNING
When an air conditioning unit is used in conjunc
tion with the furnace, the evaporator coil must be
installed in the discharge (supply) air. Do not install
an evaporator coil in the return air; excessive con
densation will occur within the furnace.
