Heil Ultimate III

When heat is needed, circulation fan starts for a bit, then pilot ignition lights for about 10 seconds. Since the main burners do not start the pilot shuts off. The circulation fan still runs. Error code is 6 flashed then 2 (6+2). Decal on furnace says this means: retry dealt-third failure to light on same call for heat -new trial for ignition after 5 minute delay. Tried resetting power but same thing happens every time.