SCHEDULED MAINTENANCE
28
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 return
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 blower
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 necessary 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
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APPEARANCE S
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.
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
service shop.
1. Dial type thermometers or thermocouple meter (option-
al) - to measure dry bulb temperature.
2. Amprobe - to measure amperage and voltage.
3. Volt-Ohm Meter - testing continuity, capacitors, and
motor windings.
4. Inclined Manometer - to measure static pressure, pres-
sure drop across coils, filters, and draft.
5. Water Manometer (12”) - to test gas inlet and manifold
pressure.
Other recording type instruments can be essential in solving
abnormal problems, however, in many instances they may
be rented from local sources.
Proper equipment promotes faster, more efficient service and
accurate repairs resulting in fewer call backs.
