Any help please. The blower is pushing out cold air. Upon turning on at the furnace port to examine operation, the blower initiates, the combustion air inducer runs for about 2 seconds, a series of clicking starts, the combustion shuts down the burners do not ignite and I am left wihth cold air blowing. The led indicators(#1 slow flash #2 steady on) indicate that the primary or secondary limit open and to check continuity or flow restrictions. Just put new filter in (the right way) because temp was dropping and did not know why. Any help from anyone. It's Saturday and I can't get a tech locally.