Gas

• For your furnace to properly work, it needs a proper gas supply. Before troubleshooting anything, make sure the gas supply valve is turned to the "On" position. Inspect the gas lines for kinks or holes.
  
  

Burner Assembly

• The burner assembly is where the gas is burned. The blower unit underneath the burner assembly blows the hot air throughout the home. To access the burners, remove the screws holding the furnace cover in place, or press on the cover access button and remove the cover. Inspect the burner assembly on the furnace’s bottom shelf for signs of soot or dirt. If sooty, have the furnace inspected by a professional. Vacuum the burners with a soft brush attachment to remove dirt.
  
  

Pilot Light

• The American Standard furnace has a pilot light assembly near the burners. A dirty pilot light orifice does not light. Do not stick anything into the orifice, as it is tinier than a pin. Use compressed air to blow out any dust from the pilot light orifice. Use the pilot light screw to adjust the flame if it appears yellow or orange instead of blue throughout. Orange in the flame means it is not strong enough.
  
  

Ignitor

• The pilot light igniter is located next to the pilot light orifice. A soiled igniter with black over its end should be pulled loose from its clamp and gently rubbed with an emery cloth. Unplug the igniter if it is not working and install in a new one. Clean the flame sensor, which is located next to the igniter, with an emery cloth if it appears soiled.