49
PRESSURE SWITCHES
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.
FLAME SENSOR
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
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS
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.
DIAGNOSTIC CHART
Refer to the Troubleshooting Chart in the back of this manual
for assistance in determining the source of unit operational prob-
lems. 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.
RESETTING FROM LOCKOUT
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
ANNUAL 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 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.
HIGH VOLTAGE !
T
O
AVOID
PERSONAL
INJURY
OR
DEATH
DUE
TO
ELECTRICAL
SHOCK
,
DISCONNECT
ELECTRICAL
POWER
BEFORE
PERFORMING
ANY
SERVICE
OR
MAINTENANCE
.
WARNING
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
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