Hi, I am getting 7 red flashes on the status indicator light for my Luxaire furnace, model GM9S060B12UP11G. The Diagnostic Fault Codes indicate "ignition lockout due to retries". The ventor motor starts as do the burners, there are several clicks heard and then the whole thing shuts down. The whole process lasts about 2 minutes and 20 seconds and the air fan never starts (it does spin freely by hand though). What is the likely cause of the problem? Thank you.

Turn off power at switch or breaker,, 1 minute turn back on,, watch it close,if it fires up and goes right back out,, try cleaning the flame senser with steel wool or very fine sandpaper