Furnace lockout results when a furnace is unable to achieve
ignition after 3 attempts during a single call for heat. It is
characterized by a nonfunctioning furnace and a "E0" 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 1-hour lockout period.
Internal control fault/no power
O P Normal operation
E 0 Lockout due to excessive retries
E 1 Low-stage pressure switch stuck closed at start of heating cycle
E 2 Low-stage pressure switch stuck open
E 3 Open high-limit switch
E 4 Flame detected when no flame should be present
E 5 Open fuse
E 6 Low flame signal
E 7 Igniter fault or improper grounding
E 8 High-stage pressure switch stuck closed at start of heating cycle
E 9 High-stage pressure switch stuck open
E A Reversed 115 VAC polarity
d 0 Data not yet on network
d 4 Invalid memory card data
To avoid personal injury or death due to electrical shock, disconnect electrical power
before performing any service or maintenance.
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
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 to 20 seconds, and 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 "Diagnostic Chart."
b 0 Blower motor not running
b 1 Blower communication error
b 2 Blower HP mismatch
b 3 Blower motor operating in power, temperature or speed limit
b 4 Blower motor current trip or lost rotor
b 5 Blower motor locked rotor
b 6 Over/under voltage trip or over temperature trip
b 7 Incomplete parameters sent to motor
b 9 Low indoor airflow
C 1 Low-stage cooling
C 2 High-stage cooling
L O Low-stage heat
F Continuous fan
1 2 CFM/100; Alternates with C1, C2, LO, HI, F