SCHEDULED MAINTENANCE
27
WARNING
HIGH VOLTAGE
Disconnect ALL power before servicing or
changing any electrical wiring. Multiple pow
-
er sources may be present. Failure to do so
may cause property damage, personal injury
or death.
MAINTENANCE
Improper filter maintenance is the most common cause of
inadequate heating or cooling performance. Filters should
be cleaned (permanent) or replaced (disposable) every two
months or as required. It is the owner’s responsibility to keep
air filters clean. When replacing a filter, it must be replaced
with a filter of the same type and size.
FILTER REMOVAL
Depending on the installation, differing filter arrangements
can be applied. Filters can be installed in the central re-
turn register, the bottom of the blower compartment (upflow
only), a side panel external filter rack kit (upflow only), or
the ductwork above a counterflow furnace. A media air filter
or electronic air cleaner can be used as an alternate filter.
The filter sizes given in the
Product Design
section of this
manual or the product
Specification Sheet
must be followed
to ensure proper unit performance. Refer to the following
information for removal and installation of filters.
FILTER REMOVAL PROCEDURE
Media Air Filter or Electronic Air Cleaner Removal
Follow the manufacturer’s directions for service.
Horizontal Unit Filter Removal
Filters in horizontal installations are located in the central
return register.
INDUCED DRAFT AND CIRCULATION
BLOWERS
The bearings in the induced draft blower and circulator blow-
er motors are permanently lubricated by the manufacturer.
No further lubrication is required. Check motor windings for
accumulation of dust which may cause overheating. Clean
as necessary.
CONDENSATE DRAINAGE SYSTEM
(QUALIFIED SERVICER ONLY)
The drain tubes, standpipe, and field supplied drain line
must be checked annually and cleaned as often as neces-
sary to ensure proper condensate drainage.
FLAME SENSOR
(QUALIFIED SERVICER ONLY)
Under some conditions, the fuel or air supply can create a
nearly invisible coating on the flame sensor. This coating
acts as an insulator, causing a drop in the flame sensing
signal. If this occurs, a qualified servicer must carefully clean
the flame sensor with steel wool. After cleaning, the flame
sensor output should be as listed on the specification sheet.
BURNERS
WARNING
HIGH VOLTAGE
Electrical components are contained in both
compartments. To avoid electrical shock, inju
-
ry or death, do not remove any internal com
-
partment covers or attempt any adjustment.
Contact a qualified service agent at once if an
abnormal flame appearance should develop.
Periodically during the heating season make a visual check of
the burner flames. Turn the furnace on at the thermostat. Wait
a few minutes since any dislodged dust will alter the normal
flame appearance. Flames should be stable, quiet, soft and
blue with slightly orange tips. They should not be yellow. They
should extend directly outward from the burner ports without
curling downward, floating or lifting off the ports.
Check the burner flames for:
1. Stable, soft and blue
2. Not curling, floating, or lifting off.
Burner Flame
TEST EQUIPMENT
Proper test equipment for accurate diagnosis is as essential
as regular hand tools.
The following is a must for every service technician and ser-
vice shop.
1. Thermometers or thermocouple meter (optional) - To
measure temperatures.
2. Multi-Meter - To measure amperage and voltage, and
to test continuity, capacitors and motor windings.
3. Manometer - To measure static pressure, pressure
drop across coils, filters and draft, and to measure in
-
let and manifold gas pressures.
Other recording type instruments can be essential in solving
abnormal problems, however, in many instances they may
be rented from local sources.
