Lennox error codes flash code troubleshooting.
Some Lennox error codes
There are 2 LEDs.
LED#1 LED#2
Simultaneous slow flash Simultaneous slow flash Normal operation
Simultaneous fast flash Simultaneous fast flash Normal call for heat
Slow flash On Limit open
Off Slow flash Pressure switch problem
Alternating slow flash Alternating slow flash Flame failure
Slow flash Off Flame sensed without gas valve on
On Slow flash Flame rollout switch open
LED#1 LED#2
Simultaneous slow flash Simultaneous slow flash Normal operation
Simultaneous fast flash Simultaneous fast flash Normal call for heat
Slow flash On Limit open
Off Slow flash Pressure switch problem
Alternating slow flash Alternating slow flash Flame failure
Slow flash Off Flame sensed without gas valve on
On Slow flash Flame rollout switch open
On, on, off                              On, off, on                                  IFC failure or wiring problem
Fast flash                               Slow flash                                   Power polarity reversed
Slow flash                              Fast flash                                    Low flame signal
Alternating fast flash              Alternating fast flash                    Low voltage or broken ignitor