Lennox OF23Q3/4-105 Installation Instructions Manual Download

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Page 11

Flue Connections

IMPORTANT

When flue pipe is installed at less than minimum
clearance listed in table 2, radiation shields must be
installed. See 13.

ÉÉÉÉÉÉÉÉ

1" (25 mm)

min

Figure 13

combustible

material

Radiation Shield Installation

OF23 unit

(top)

of23 unit

(front)

radiation

shields

flue

pipe

unit

cabinet

NOTE 1−Radiation shields must be constructed of 24 gauge sheet
metal

minimum

NOTE 2−Radiation shields required when A is less than 9" (229 mm).

NOTE 3−Radiation shields should extend from the top of the unit to
the top of the flue pipe.

noncombustible

spacers

radiation shields

(see note 1)

12" (305 mm)

min

7" (178 mm)

min

see note 2

see note 3

For front flue models, the enclosed exhaust pipe ring may
be used for pipe to exit the left or right side of cabinet. Cen-
ter line marks are provided in cabinet.

Use 24 gauge or heavier galvanized smoke pipe and fit-
tings to connect furnace to vent. Connect flue pipe to chim-
ney using the least number of elbows and angles possible.
Flue pipe or vent connector must be inserted into but not
beyond the outside wall of the chimney flue. No reduction in
diameter of flue pipe is acceptable. It is best to have flue
pipe as short and direct as possible. Where two or more ap-
pliances vent into a common flue, the area of the common
flue should be at least equal to the area of the largest flue or

vent connector, plus 50% of the area of any additional flues
or vent connectors. Install the barometric draft control (pro-
vided) and flue pipe according to instructions packed with
control.

Inspect flue pipe annually. Clean soot or ash from flue pipe,
if necessary. If pipe is rusted, replace.

Install draft control at least 12 inches beyond the furnace. If
there is no space to install the draft control in the flue pipe it
may be installed in the vent above the flue pipe. Follow the
instructions packed with the draft control.

Alternate Side Flue Connections

The vent pipe may exit the top or sides of the cabinet. A
hole is provided in the top cap for top exit. For side exit, lo-
cate the center hole punched in the side of the cabinet. See
unit dimensions on page 2. Using it as the center point, cut
a 6 inch (152 mm) round hole in the cabinet’s side. Using it
as the center point, cut a 6 inch (152 mm) round hole in the
cabinet’s side. Install the barometric draft control within 18
inches of the furnace flue outlet. Attach the provided finish-
ing plate to cover rough edges.

Supply & Return Air Plenums

Secure return air plenum to unit using sheet metal screws.

NOTE − The following are suggested procedures that
should be followed when installing the supply air plenum.

1− Use sealing strips of fiberglass.
2− In all cases, the plenum should be secured to furnace

or evaporator cabinet with sheet metal screws.

3− Install supply and return air ducts as desired.

Oil Supply Lines Sizing

Ensure that the restrictions of the piping system, plus any
lift involved, do not exceed the capability of the oil pump.
Use the following guidelines when determining whether to
use a single−or two−stage oil pump.

One−Pipe System

When using a one−pipe system with the oil tank above the
burner and a vacuum of 6" (152 mm) Hg or less, a single−
stage fuel pump with a supply line and no return line should
be adequate. See figure 14. Manual bleeding of the fuel
pump is required on initial start up. Failure to bleed air from
the oil pump could result in an air lock/oil starvation condi-
tion.

NOTE − As an extra precaution, cycle heating on and off ten
times after bleeding air from the oil pump. This will elimi-
nate air in the gun assembly.

To determine the length of the run for piping, refer to table 2
.