Lennox Pulse 21 Shuts Down

[Brick Guy]

I have a Lennox Pulse furnace. M/N G21Q4/5-100-3. The unit starts but does not continue running. The blower does not kick on when it calls for heat. Sometimes, however, everything works fine. I have replaced the controller and the gas flapper. I also have drained the water in the stand pipe. I now have determined if I leave the blower in the "on" position rather than the "auto" position, everything works fine. What is the solution to my problem?
Thanks...Brick Guy.

[heatpumpguru]

Call a PRO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!

[Brick Guy]

I already had our dealer look at it. We live in a small rural town.

[HeyBob]

Sorry, this is not a DIY help site. Please review the rules, there is a link in my signature line.

Call another Lennox dealer to straighten out your furnace, the first guy obviously missed it!