[redz1006]

I have a 3 yr old Comfortmaker Environplus 90 furnace used for heating and cooling. It suddenly developed a problem with the flame
not staying lit. When I reset the furnace, I did notice that the
automatic igniter will light the flame but the flame will only be lit for a few seconds after the system shuts it off again. It does this about 5 times more, then the system will stops trying. I believe this is part of the systems safety feature. I have new filters and airflow
is good. The fan is working fine when in "on" mode. Correct me if I'm wrong, but I think the next step on the cycle after lighting the flame is to turn on the fan/blower. This is not happening at all.

This is what I think could be wrong :

1)Igniter assembly is bad
2)Bad or dirty flame sensor
3)High switch not calibrated correctly (or stuck)
4)Gas valve control syste bad.

Any thoughts ?

I have to admit, aside from changing the filters and the aluminum
grates for the humidifier, I have done no preventive maintenance.

Also, the LED for the W wire is blinking in the Aprilaire zone controller mother board (I have dual zone) .
I know the the W wire in the thermostat controls the gas burner.
I believe the number of blinks mean something too. DO you know where
can I get information to interpret the blinks ?

Gotta ask first before calling it in.........Thanks in advance.