furnace wont light

i have a airease hvac furnace when it turns on pilot light comes on but no flame and it just blows cold air if u cycle power off and on on furnace it works normally till next time heat is demanded by themostat

 

Common cause is the pilot orifice, down by the tip, needs cleaning, and/ or it's flame sensing ability. Often these two go hand in hand. You need a good pilot flame for good detection of flame, that the circuit board can acknowledge.

Could be other things though also. And we often tell people to go your furnace and watch what your sequence of operation is doing, so you can better inform us, so we can help you maybe faster. You can open the big furnace door and watch and see if you have ignition of some type, and then if you have the burner come on, and then if it goes out, about how many seconds after you have ignition, does the burner go out.