My gas furnace is not igniting when the demand calls for it. The LED is lighting 1 short and 2 longs. I think all is working but once it calls for heat it doesn't work. What does the LED code mean?

My first guess is that it could be the hot surface igniter (HSI). This is what ignites the gas. If I remember correctly, there is a self-test mode for that furnace that will step through each of the components of the furnace so you can see what is working and what is not. This should be listed on the cover that you have to remove to get to the burners, etc. The procedure is quite easy to follow.

Hope that it is the HSI, because it is one of the easiest items to replace. Probably around $20-30.

Best of luck,
Wally H.