Goodman GMEC80 Service Instructions Manual page 22

Diagnostic Chart
Refer to the Troubleshooting Chart in the back of this manual
for assistance in determining the source of unit operational
problems.
External Lockout
- A control lockout resulting from an external fault
sensed by the control, such as an unsuccessful re-
cycle or retry period, or a limit trip. Once in External
Lockout, the control will shut down for a period of
one hour before attempting another trial for ignition.
Internal Lockout
- A failure internal to the control board.
Fault Recall
Retrieving Fault Codes
To retrieve fault codes, push and release the "LAST ER-
ROR" button for more than 1/5 second and less than 5
seconds (the LED will indicate this period by solid GREEN
for 1/5 second to 5 seconds). The LED will flash up to
five stored fault codes, beginning with the most recent. If
there are no fault codes in memory, the LED will flash two
green flashes. The control will flash the most recent error
first and the oldest error last. If multiple faults exist there
will be 2 seconds between codes. Solid LED error codes
will not be displayed.
Fault Code Reset
To clear the fault code memory, push and hold the "LAST
ERROR" button for more than 5 seconds and less than
10 seconds (the LED will indicate this period by RAPID
GREEN FLASH for 5 seconds to 10 seconds). The LED
will flash three green flashes when the memory has been
cleared.
The ignition control is equipped with a momentary push
button switch that can be used to display on the diagnostic
LED the last five faults detected by the control. The control
must be in Standby Mode (no thermostat inputs) to use
the feature.
Depress the push button switch for approximately 2 sec-
onds. Release the switch when the LED is turned off. The
diagnostic LED will then display the flash codes associated
with the last five detected faults. The order of display is the
most recent fault to the least recent fault.
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 one
flash diagnostic LED code. If the furnace is in "lockout", it
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 for 1 - 20 seconds.
3. Manual thermostat cycle. Lower the thermostat so that
there is no longer a call for heat then reset to previous
setting. Interrupt thermostat signal to the furnace for
1 - 20 seconds.