Intake Piping - Lennox G43UF SERIES Unit Information

TYPICAL AIR INTAKE PIPE CONNECTIONS
UPFLOW DIRECT VENT APPLICATIONS
(Right-Hand Exit Shown)
PLUG
(Must be
glued in
place)

Intake Piping

The G43UF furnace may be installed in either direct vent
or non−direct vent applications. In non−direct vent applica-
tions, when intake air will be drawn into the furnace from the
surrounding space, the indoor air quality must be consid-
ered and guidelines listed in Combustion, Dilution and Ven-
tilation Air section must be followed.
The G43UF unit is designed for either left−side or right−side
air intake connections. Intake air piping is independent of
exhaust piping.
Follow the next four steps when installing the unit in Direct
Vent applications, where combustion air is taken from out-
doors and flue gases are discharged outdoors. The pro-
vided air intake screen must not be used in direct vent ap-
plications.
1 − Cement intake piping in slip connector located on the
side of the burner box.
2 − Use a sheet metal screw to secure the intake pipe to the
connector, if desired. A pilot indentation is provided in the
slip connector to assist in locating and starting the fasten-
er.
3 − Glue the provided 2" plug into the unused air intake con-
nector on the opposite side of the cabinet.
4 − Route piping to outside of structure. Continue with instal-
lation following instructions given in general guide lines for
piping terminations and in intake and exhaust piping ter-
minations for direct vent sections. Refer to figure 21 for
pipe sizes.
TRANSITION
2
2
2
G43UF−24B−045
G43UF−24B−070
G43UF−36B−070
G43UF−36C−090
G43UF−48C−090
G43UF−48C−110
G43UF60C−110
FIGURE 21
NOTE − Debris screen and elbow may be rotated, so that
screen may be positioned to face forward, backward or
downward.
Page 24
2−1/2",
3" OR
4
2 *
TRANSITION
2 *
2
G43UF−24B−045
G43UF−24B−070
G43UF−36B−070
G43UF−36C−090
G43UF−48C−090
G43UF−48C−110*
G43UF−60C−110*
*Pipe length must be limited
to 2" in G43UF−110 and −135
applications.
TYPICAL AIR INTAKE PIPE CONNECTIONS
UPFLOW NON-DIRECT
VENT APPLICATIONS
(Right-Hand Exit Shown)
PLUG
(Must be
glued in
place)
FIGURE 22
2−1/2",
3" OR
4
2"*
G43UF−24B−045
G43UF−24B−070
G43UF−36B−070
G43UF−36C−090
G43UF−48C−090
G43UF−48C−110*
G43UF−60C−110*
G43UF−60D−135*
6 in. Max.
INTAKE
DEBRIS
SCREEN
(Provided)