I'm dealing with a 22-year-old furnace that refuses to turn on for heating. The hot surface ignitor isn't glowing, and I've already replaced it. I've checked for voltage and confirmed it's functioning. Additionally, I replaced the flame sensor. Currently, the furnace is showing a code 34 and locks out with code 14 after three attempts. I've tested all stages of operation with a multimeter, ensuring everything's getting the right voltage until it should send 120 volts to the ignitor. The unit also leaked water from the central air over the summer, which makes me think the condensation line could be clogged or the control board might be faulty—or maybe both. If the ignitor isn't receiving 120 volts, does that mean the control board definitely needs to be replaced, or should I first look into clearing the condensation line? Any advice would be greatly appreciated, especially since a new control board costs around $400!
2 Answers
I've had the same issue before, and I found a replacement board on eBay for about $40. There are tons of sellers with parts from older furnaces, so you might find a good deal if you look around!
If everything else is working but the board isn't sending power to the hot surface ignitor, it's likely that the control board is the issue. That's what happened to my furnace, and replacing the board fixed it! Just make sure to double-check all your connections first.
Totally possible. Definitely something you should check before splurging on a new board.
Yeah, I agree. It sounds pretty definitive that the board's the problem if nothing else is misbehaving.