. I see it igniting and hear a gas hissing sound however the blower does not come on. The furnace repeats the steps of igniting and gas coming out but does not blow. I did get it to work a few times but not conssistantly. Freezing at night please help?

If it lights and then right back off after 3 seconds, I would say you have a dirty flame sensor. You will need to srape it off with a knife or steel wool. TURN POWER OFF FIRST!! You should have a blinking light on the furnace control board telling why the system did not light.

Thanks T-top. I scraped it with a steel wool but it didn't look like it had anything on it. It is still not working, I'm thinking it might be the circuit board but I don't understand how it could be the circuit board when it turns on once in awhile and blows.