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SERVICE AND MAINTENANCE
PROCEDURES
CA
UN Le
FIRE, INJURY OR DEATH HAZARD
Failure
to
follow
this
warning
could
result
in
personal
injury, death and/or property damage.
The
ability
to
properly
perform
maintenance
on_
this
equipment
requires certain knowledge,
mechanical
skills,
tools, and equipment. If you do not possess these, do not
attempt to perform
any service and maintenance
on this
equipment other than those procedures recommended in the
Owner's Manual.
4&
CAUTION
ENVIRONMENTAL
HAZARD
Failure to follow this caution may result in environmental
pollution.
Remove
and recycle all components or materials (i.e. oil,
refrigerant, control board, etc.) before unit final disposal.
CA
AUN Le
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.
4&
CAUTION
ELECTRICAL OPERATION HAZARD
Failure
to follow
this
caution
may
result
in improper
furnace operation or failure of furnace.
Label
all wires
prior
to
disconnection
when
servicing
controls. Wiring errors can cause improper and dangerous
operation.
General
These instructions are written as if the furnace is installed in an
upflow application. An upflow furnace application is where the
blower is located below the combustion and controls section of the
furnace,
and
conditioned
air is discharged
upward.
Since
this
furnace can be installed in any of the 4 positions shown in Fig. 2,
you
must
revise
your
orientation
to
component
location
accordingly.
Electrical Controls and Wiring
CA
UN Le:
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
There may be more than one electrical supply to the furnace.
Check accessories and cooling unit for additional electrical
supplies that must be shut off during furnace servicing. Lock
out and tag switch with a suitable warning label.
The
electrical ground
and
polarity
for
115-v
wiring
must
be
properly maintained. Refer to Fig. 35 for field wiring information
and to Fig. 65 for furnace wiring information.
NOTE:
If the polarity is not correct, the STATUS
LED
on the
control will flash rapidly and prevent the furnace from heating. The
control system also requires an earth ground for proper operation
of the control and flame-sensing electrode.
The 24-v circuit contains an automotive-type, 3-amp. fuse located
on the control.
See Fig. 36. Any shorts of the 24-v wiring during
installation, service, or maintenance will cause this fuse to blow. If
fuse replacement is required, use ONLY a 3-amp. fuse. The control
LED will display status code 24 when fuse needs to be replaced.
Troubleshooting
Refer to the service label.
See Fig. 56.
The
Troubleshooting
Guide
can
be
a useful
tool
in isolating
furnace
operation
problems.
Beginning
with
the word
"Start,"
answer each question and follow the appropriate arrow to the next
item.
See Fig. 64.
The Guide will help to identify the problem or failed component.
After replacing any component, verify correct operation sequence.
Proper instrumentation is required to service electrical controls.
The control in this furnace is equipped with a Status Code LED
(Light-Emitting
Diode)
to
aid
in
installation,
servicing,
and
troubleshooting.
Status codes can be viewed
at the indicator in
blower
door.
The
amber
furnace
control
LED
is either
ON
continuously, rapid flashing, or a code composed of 2 digits. The
first digit is the number of short flashes, the second digit is the
number of long flashes.
For an explanation of status codes, refer to service label located on
control door or Fig. 56, and the troubleshooting guide which can
be obtained from your distributor.
Retrieving Stored Fault Codes
NOTE:
Fault codes cannot be retrieved if a thermostat signal
(24-v on W, Y, G, etc.) is present, or if any delays such as blower
off-delays are active.
The
stored status codes will NOT
be erased from
the control
memory when 115- or 24-v power is interrupted. See the Service
Label (Fig. 56) for more information. The most recent fault code
may be retrieved as follows:
1. Leave 115-v power connected to furnace.
2. Observe the status LED through the blower door (the lower
door on upflow applications) indicator. Refer to the Service
Label (Fig. 56) to interpret the LED.
3. Remove the Main/Control door (the upper door on upflow
installations).
4. BRIEFLY disconnect and reconnect ONE of the main limit
wires.
5. The LED will flash the last stored fault code. Refer to the
Service Label (Fig. 56) to interpret the LED.
6. A component test sequence will follow.
7. Reinstall the Main/Control door.
70
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