A concerning thing happened tonight: our upstairs furnace abruptly shut off. I heard it start up… and soon after, shut down.
I ende up turning the furnace off, and waited a bit… but on starting it back up again, it went through the same process. It would begin, I could hear the flame catch, and then it shut down.
Having experienced something like this before, Bob taught me to look for an LED light – which is a kind of diagnostic indicator. Observing this light can provide insight into what’s wrong with the furnace.
I looked and saw it blink once, then a long pause, then another blink. I opened up the front panel, jotted down the model number, and went looking online for a reference manual.
I learned that the code was for the furnace not able to properly detect combustion. Which was odd, because I could see that the flame was catching. I learned that there was a lockout that occurred after three attempts, and that was what was going on with the furnace.
With the panel open, I tried starting it up again… and to my surprise, it caught. Not sure what really happened there, but the added airflow seemed to do the trick. I closed the panel up, and it’s been working fine ever since.
I’m just going to leave this here: