SYSTEM OPERATION
23
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.
Burner Flame
TROUBLESHOOTING
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
WARNING
High Voltage!
To avoid personal injury or death
due to electrical shock, disconnect
electrical power before performing
any service or maintenance.
Refer to the
Troubleshooting Chart
in the back of this
manual for assistance in determining the source of unit
operational problems. The 7-segment LED displays 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
an
EE0
code displayed on the 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.
