46
P
RESSURE
S
WITCHES
The pressure switches are normally-open (closed during
operation) negative air pressure-activated switches. They
monitor the airflow (combustion air and flue products)
through the heat exchanger via pressure taps located on the
induced draft blower and the coil front cover. These switches
guard against insufficient airflow (combustion air and flue
products) through the heat exchanger and/or blocked
condensate drain conditions.
F
LAME
S
ENSOR
The flame sensor is a probe mounted to the burner/manifold
assembly which uses the principle of flame rectification to
determine the presence or absence of flame.
T
ROUBLESHOOTING
E
LECTROSTATIC
D
ISCHARGE
(ESD) P
RECAUTIONS
NOTE:
Discharge body’s static electricity before touching
unit. An electrostatic discharge can adversely affect electrical
components.
Use the following precautions during furnace installation and
servicing to protect the integrated control module from
damage. By putting the furnace, the control, and the person
at the same electrostatic potential, these steps will help avoid
exposing the integrated control module to electrostatic
discharge. This procedure is applicable to both installed
and uninstalled (ungrounded) furnaces.
1. Disconnect all power to the furnace. Do not touch the
integrated control module or any wire connected to the
control prior to discharging your body’s electrostatic
charge to ground.
2. Firmly touch a clean, unpainted, metal surface of the
furnace away from the control. Any tools held in a
person’s hand during grounding will be discharged.
3. Service integrated control module or connecting wiring
following the discharge process in step 2. Use caution
not to recharge your body with static electricity; (i.e., do
not move or shuffle your feet, do not touch ungrounded
objects, etc.). If you come in contact with an ungrounded
object, repeat step 2 before touching control or wires.
4. Discharge your body to ground before removing a new
control from its container. Follow steps 1 through 3 if
installing the control on a furnace. Return any old or new
controls to their containers before touching any ungrounded
object.
HIGH VOLTAGE !
T
O
AVOID
PERSONAL
INJURY
OR
DEATH
DUE
TO
ELECTRICAL
SHOCK
,
DISCONNECT
ELECTRICAL
POWER
BEFORE
PERFORMING
ANY
SERVICE
OR
MAINTENANCE
.
WARNING
D
IAGNOSTIC
C
HART
Refer to the
Troubleshooting Chart
in the back of this manual
for assistance in determining the source of unit operational
problems. The dual 7-segment LED display will display an
error code that may contain a letter and number. The error
code may be used to assist in troubleshooting the unit.
R
ESETTING
F
ROM
L
OCKOUT
Furnace lockout results when a furnace is unable to achieve
ignition after three attempts during a single call for heat. It
is characterized by a non-functioning furnace and a
E 0
code
displayed on the dual 7-segment display. If the furnace is in
“lockout”, it will (or can be) reset in any of the following
ways.
1. Automatic reset. The integrated control module will
automatically reset itself and attempt to resume normal
operations following a one hour lockout period.
2. Manual power interruption. Interrupt 115 volt power to the
furnace.
3. Manual thermostat cycle. Lower the thermostat so that
there is no longer a call for heat for 1 -20 seconds then
reset to previous setting.
NOTE:
If the condition which originally caused the lockout
still exists, the control will return to lockout. Refer to the
Troubleshooting Chart
for aid in determining the cause.
M
AINTENANCE
T
O
AVOID
ELECTRICAL
SHOCK
,
INJURY
OR
DEATH
,
DISCONNECT
ELECTRICAL
POWER
BEFORE
PERFORMING
ANY
MAINTENANCE
. I
F
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
.
WARNING
A
NNUAL
I
NSPECTION
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 furnace components are in proper working
order and that the heating system functions appropriately.
Pay particular attention to the following 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.
