32
XIX. MAINTENANCE
WARNING
T
O AVOID ELECTRICAL SHOCK, INJURY OR DEATH, DISCONNECT ELECTRICAL
POWER BEFORE PERFORMING ANY MAINTENANCE. IF YOU MUST HANDLE THE
IGNITER, HANDLE WITH CARE.
T
OUCHING THE IGNITER ELEMENT WITH BARE
FINGERS, ROUGH HANDLING, OR VIBRATION COULD DAMAGE THE IGNITER
RESULTING IN PREMATURE FAILURE.
O
NLY A QUALIFIED SERVICER SHOULD
EVER HANDLE THE IGNITER.
A
NNUAL
INSPECTION
The furnace should be inspected by a qualified installer, or service
agency at least once per year. This check should be performed at
the beginning of the heating season. This will ensure that all fur-
nace components are in proper working order and that the heating
system functions appropriately. Pay particular attention to the fol-
lowing items. Repair or service as necessary.
•
Flue pipe system. Check for blockage and/or leakage. Check
the outside termination and the connections at and internal
to the furnace.
•
Heat exchanger. Check for corrosion and/or buildup within
the heat exchanger passageways.
•
Burners. Check for proper ignition, burner flame, and flame
sense.
•
Drainage system. Check for blockage and/or leakage.
Check hose connections at and internal to furnace.
•
Wiring. Check electrical connections for tightness and/or
corrosion. Check wires for damage.
•
Filters.
F
ILTERS
CAUTION
T
O ENSURE PROPER UNIT PERFORMANCE, ADHERE TO THE FILTER SIZES
GIVEN IN THE
P
RODUCT
D
ATA
B
OOK APPLICABLE TO YOUR MODEL*.
M
AINTENANCE
Improper filter maintenance is the most common cause of inad-
equate heating or cooling performance. Filters should be cleaned
(permanent) or replaced (disposable) every two months or as re-
quired. When replacing a filter, it must be replaced with a filter of
the same type and size.
F
ILTER
R
EMOVAL
Depending on the installation, differing filter arrangements can be
applied. Filters can be installed in either the central return register
or a side panel external filter rack (upflow only). A media air filter or
electronic air cleaner can be used as an alternate filter. Follow the
filter sizes given in the Recommended Minimum Filter size table to
ensure proper unit performance.
To remove filters from an external filter rack in an upright upflow
installation, follow the directions provided with external filter rack
kit. To remove internal filters see
Internal Filter Removal
section.
Internal filters are an accessory item and are not included with
your furnace. For further details, see your distributor.
H
ORIZONTAL
U
NIT
F
ILTER
R
EMOVAL
Filters in horizontal installations are located in the central return
register or the ductwork near the furnace.
To remove:
1. Turn OFF electrical power to furnace.
2. Remove filter(s) from the central return register or ductwork.
3. Replace filter(s) by reversing the procedure for removal.
4. Turn ON electrical power to furnace.
M
EDIA
A
IR
F
ILTER
OR
E
LECTRONIC
A
IR
C
LEANER
R
EMOVAL
Follow the manufacturer’s directions for service.
B
URNERS
Visually inspect the burner flames periodically during the heating
season. Turn on the furnace at the thermostat and allow several
minutes for flames to stabilize, since any dislodged dust will alter
the flames normal appearance. Flames should be stable, quiet,
soft, and blue (dust may cause orange tips but they must not be
yellow). They should extend directly outward from the burners with-
out curling, floating, or lifting off. Flames must not impinge on the
sides of the heat exchanger firing tubes.
I
NDUCED
D
RAFT
AND
C
IRCULATOR
B
LOWERS
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.
C
ONDENSATE
T
RAP
AND
D
RAIN
S
YSTEM
(Q
UALIFIED
S
ERVICER
O
NLY
)
Annually inspect the drain tubes, drain trap, and field-supplied drain
line for proper condensate drainage. Check drain system for hose
connection tightness, blockage, and leaks. Clean or repair as
necessary.
F
LAME
S
ENSOR
(Q
UALIFIED
S
ERVICER
O
NLY
)
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 sense signal. If the flame
sense signal drops too low the furnace will not sense flame and
will lock out. The flame sensor should be carefully cleaned by a
qualified servicer using emery cloth or steel wool. Following clean-
ing, the flame sense signal should be 1 to 4 microamps at 115
volts.
F
LUE
P
ASSAGES
(Q
UALIFIED
S
ERVICER
O
NLY
)
The heat exchanger flue passageways should be inspected at the
beginning of each heating season. If necessary, clean the pas-
sageways as outlined below.
1. Turn OFF the electrical power and gas supply to the furnace.
2. Disconnect the gas line and remove the burner/ manifold
assembly by removing the screws securing the assembly
to the partition panel.
3. Disconnect the flue pipe system from the induced draft
blower.
4. Remove the induced draft blower and, drain and pressure
tap hoses from the recuperator coil front cover.
5. Remove the recuperator coil front cover to expose the coil
tubes and turbulators.
6. Remove the recuperator coil turbulators individually by slowly
pulling each turbulator forward firmly.
7. Clean the recuperator coil tubes using a long handle wire
brush, such as a gun cleaning brush.
8. Clean the primary heat exchanger tubes using a wire brush
attached to a length of high grade stainless steel cable,
such as drain cleanout cable. Attach a variable speed
reversible drill to the other end of the cable. Slowly rotate
the cable with the drill and insert it into one of the heat
exchanger tubes. While reversing the drill, work the cable
in and out several times to obtain sufficient cleaning. Repeat
for each tube.
