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Filters
All ML180UHE filters are installed external to the unit. Fil
-
ters should be inspected monthly. Clean or replace the
filter( s) when necessary to ensure proper furnace opera
-
tion.
A filter must be in place when the unit is operat
-
ing.
See table 1 for recommended filter sizes.
NOTE -
Use replacement filters that are similar in size
and efficiency ratings to those originally provided by the
installing contractor. Use of replacement filters with higher
filtration ratings may restrict air flow to the furnace. This
may result in reduced unit efficiency, as well as premature
blower motor failure.
TABLE 1
Furnace
Cabinet Width
Filter Size
Side Return
Bottom Return
14-1/2”
16 X 25 X 1 (1)
14 X 25 X 1 (1)
17-1/2”
16 X 25 X 1 (1)
16 X 25 X 1 (1)
21”
16 X 25 X 1 (1)
20 X 25 X 1 (1)
24-1/2”
16 X 25 X 1 (2)
24 X 25 X 1 (1)
Maintenance
A licensed professional service technician (or equivalent)
should inspect the complete system each season (heat
-
ing and cooling). The following maintenance procedures
should only be conducted by a licensed professional ser
-
vice technician (or equivalent).
Do not attempt to service
the unit in any way.
WARNING
ELECTRICAL SHOCK, FIRE,
OR EXPLOSION HAZARD.
Failure to follow safety warnings exactly could
result in dangerous operation, serious injury, death
or property damage. Improper servicing could result
in dangerous operation, serious injury, death, or
property damage. Before servicing, disconnect all
electrical power to furnace.
When servicing controls, label all wires prior
to disconnecting. Take care to reconnect wires
correctly. Verify proper operation after servicing.
CAUTION
To ensure proper operation, a licensed professional
service technician (or equivalent) should check the
burner flame and conduct a combustion analysis
annually.
Annually (before heating season) inspect furnace venting
system, vent cap, heat exchanger and burners for corro
-
sion, deterioration, or deposits of debris. Remove any ob
-
structions.
Inspect the furnace venting system to make sure it is in
place, physically sound and without holes, corrosion, or
blockage. The vent connector must be correctly posi
-
tioned and sloped upward. The vent connector must be
physically sound, without holes or excessive corrosion.
Inspect the furnace return air duct connection. The duct
must be sealed to the furnace and it must terminate out
-
side the space containing the furnace.
Inspect the physical support of the furnace to guarantee
that it is sound. The support must not sag and must not
have cracks or gaps around the base of the furnace. There
must be a seal between the furnace base and the support.
During a seasonal check, the service technician will in
-
spect the indoor blower and the burner flames along with
the venting system.
Blower
Check blower wheel for any debris and clean it, if nec
-
essary. The blower motor is pre-lubricated for extended
bearing life. No further lubrication is needed.
WARNING
The blower access panel must be securely in place
when the blower and burners are operating. Gas
fumes, which could contain carbon monoxide, can
be drawn into living space resulting in personal
injury or death.
Service Reminder
Call your Lennox service technician if the unit will not op-
erate. Before calling, always check the following to be
sure service is required.
1 -
Check that electrical disconnect switches are
ON
.
2 -
Check room thermostat for proper setting.
3 -
Replace any blown fuses or reset circuit breakers.
4 -
Gas valve should be
ON
.
5 -
Air filter should not be plugged, which will limit air
flow.
6 -
Is gas turned on at meter?
7 -
Is manual main shut-off valve open?
Record the model and serial number of the furnace. These
numbers are on the unit nameplate, which is located be
-
low the burners.
Serial Number ________________________________
Model Number ________________________________
