SERVICE AND TECHNICAL SUPPORT MANUAL
Gas Furnace: (F/G)9MXT
Specifications subject to change without notice.
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Care and Maintenance
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
Never store flammable or combustible materials on,
near, or in contact with the furnace, such as:
1. Spray or aerosol cans, rags, brooms, dust
mops, vacuum cleaners, or other cleaning
tools.
2. Soap powders, bleaches, waxes or other
cleaning compounds, plastic or plastic
containers, gasoline, kerosene, cigarette lighter
fluid, dry cleaning fluids, or other volatile fluids.
3. Paint thinners and other painting compounds,
paper bags, or other paper products. Exposure
to these materials could lead to corrosion of the
heat exchangers.
!
WARNING
For continuing high performance and to minimize possible
furnace failure, periodic maintenance must be performed on
this furnace. Consult your local dealer about proper frequency
of maintenance and the availability of a maintenance contract.
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Turn off the gas and electrical supplies to the furnace
and install lockout tag before performing any
maintenance or service. Follow the operating
instructions on the label attached to the furnace.
!
WARNING
CARBON MONOXIDE POISONING AND FIRE
HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
Never operate furnace without a filter or filtration
device installed. Never operate a furnace with filter or
filtration device access doors removed.
!
WARNING
CUT HAZARD
Failure to follow this caution may result in personal
injury.
Sheet metal parts may have sharp edges or burrs.
Use care and wear appropriate protective clothing,
safety glasses and gloves when handling parts, and
servicing furnaces.
CAUTION
!
The minimum maintenance on this furnace is as follows:
1. Check and clean air filter each month or more frequently
if required. Replace if torn.
2. Check blower motor and wheel for cleanliness each
heating and cooling season. Clean as necessary.
3. Check electrical connections for tightness and controls
for proper operation each heating season. Service as
necessary.
4. Inspect burner compartment before each heating season
for rust, corrosion, soot or excessive dust. If necessary,
have furnace and burner serviced by a qualified service
agency.
5. Inspect the vent pipe/vent system before each heating
season for water leakage, sagging pipes or broken
fittings. Have vent pipes/vent system serviced by a
qualified service agency.
6. Inspect any accessories attached to the furnace such as
a humidifier or electronic air cleaner. Perform any service
or maintenance to the accessories as recommended in
the accessory instructions.
Cleaning and/or Replacing Air Filter
The air filter type may vary depending on the application or
orientation. The filter is external to the furnace casing. There
are no provisions for an internal filter with this furnace. See
“Filter Arrangement” under the “Installation” section of this
manual.
NOTE
: If the filter has an airflow direction arrow, the arrow
must point toward the blower.
To clean or replace filters, proceed as follows:
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failure to follow this warning could result in personal
injury or death, or property damage.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF
position and install a lockout tag. There may be more
than one disconnect switch. Lock out and tag switch
with a suitable warning label. Verify proper operation
after servicing.
!
WARNING
1. Turn off electrical supply to furnace.
2. Remove filter cabinet door.
3. Slide filter out of cabinet.
4. If equipped with permanent, washable filter, clean filter by
spraying cold tap water through filter in opposite direction
of airflow. Rinse filter and let dry. Oiling or coating of the
filter is not recommended.
5. If equipped with factory specified disposable media filter,
replace only with a factory specified media filter of the
same size.
6. Slide filter into cabinet.
7. Replace filter cabinet door.
8. Turn on electrical supply to furnace.
Blower Motor and Wheel Maintenance
To ensure long life, economy, and high efficiency, clean
accumulated dirt and grease from blower wheel and motor
annually.
The inducer and blower motors are prelubricated and require
no additional lubrication. These motors can be identified by the
absence of oil ports on each end of the motor.
The following items should be performed by a qualified service
technician. Clean blower motor and wheel as follows:
1. Turn off electrical supply to furnace.
2. Remove blower door.
