Filter
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# 44886B001 Page 3
Upflow Units
To replace the filter in an upflow unit, refer to the following
directions and Figure 2.
Side Return
To replace the filter in a furnace with an external filter rack or
cabinet on either side of the furnace cabinet:
1. Turn off the power to unit.
2. The filter(s) may be removed by sliding toward the front.
Replace in a reverse procedure.
Bottom Return
To replace the filter in a furnace with a bottom return air:
1. Turn off the power to unit.
2. Remove lower front panel by lifting up and pulling out.
3. The filter(s) may be removed by sliding toward the front.
Replace in a reverse procedure.
airflow. This can cause heat exchanger failure or cooling coil
freeze-up along with the accompanying costly service calls.
The dealer may have changed the filter size, so the information
provided in Table 1 may not apply to your installation.
Always measure the original filter and replace with the
same size and type.
Basement Units
To replace the filter in a basement unit (see Figure 3):
1. Turn off power to unit.
2. Remove lower rear panel by lifting up and pulling out.
3. The filter(s) may be removed by sliding out through the rear
of the furnace. To reinsert, place filter on the two filter
supports and slide into unit.
Restore power to the furnace after the door or panel has been
replaced and check furnace for proper operation. If the unit
does not operate, call your dealer for service.
Lubrication
Lubrication of the bearings in the circulating air blower motor
and the combustion blower motor is not recommended.
Combustion and Ventilation Air
Adequate air must reach your furnace to provide for proper and
safe operation. Any obstruction of this airflow can cause an
unsafe condition which may result in death or permanent
injury. Lethal carbon monoxide gas can be produced if
combustion air is restricted.
Furnaces located in a closet, alcove, or utility room must have
provision for adequate air supply by means of upper and lower
grilles in the door, or by the introduction of outside air, or both.
National codes and local code requirements are generally alike.
However, local codes take precedence.
Venting and Furnace Support
Venting of this furnace must comply with our published instruc-
tions. If the installer has not followed these requirements, you
should request the installer to comply as soon as possible.
Make sure all flue product materials external to the furnace are
clear and free of any obstruction, slope upward, and have no
holes or leaks.
It is important that the outside area where the vent terminates is
kept clear of any obstructions which might block or impede the
venting of the furnace.
Should any unusual conditions be observed during your
inspections, call your authorized service dealer at once.
Return Air
Check that all return air duct connections are tight and sealed
to the furnace cabinet and that all return air grilles or registers
are located outside the space containing the furnace.
Side Return
Bottom Return
R/A
Duct
Filter Rack
Filter
(slides in from front of unit)
Filter
Base
Side
Panel
Front
Panel
Upflow Units: Filter Replacement
Figure 2
Filter
Rear
Of
Furnace
Filter
Supports
Basement Units: Filter Replacement
Figure 3
Table 1
sledoMeziS
FUL/R"52x"61
)59/48,27/75(RBL/R,FBL/R"91x"81
)521/211(RBL/R,FBL/R"12x"91
)861/041(RBL/R"61/7-22x"8/1-02
)691/861(RBL/R"8/3-42x"8/5-42
Factory-Supplied Filters
Models R/LHF and R/LHR are not equipped with factory-
supplied filters. The filters for these units are supplied in
the field.