I have a Carrier WeatherMaker 9200 that works fine..except when the burner turns off. Then, intermittently, it makes a groaning noise that sounds like a chair being dragged across a hard floor. This noise sometimes doesn't happen, sometimes lasts just a moment, sometimes it goes on for a minute or more. It's very loud and can be heard throughout the house and even outside of the house. There is no noise on startup. There is no issue starting up, there is no issue running. There are no error codes. The thermostat clicks to end the heat cycle, the burner turns off, this noise may or may not happen (but if the noise does happen, this is the only time when it will), and regardless of the noise, the furnace goes through its normal cool down and shutdown sequence. I had a tech come out, and it never made a peep, but he came to the conclusion that it had to be the draft inducer, though it works fine and doesn't make a sound. I believe it was simply that he had no other explanation. My intuition says it could be the gas valve or gas valve mechanism. I'd appreciate any opinions or troubleshooting ideas.

Hi everyone, I have an 8 year old Coleman furnace that is having ignition issues. What happens is the furnace fan turns on as normal when heating is required, and then gas begins to flow in. After that the furnace might light, other times it does not. Sometimes it will light after the second or third attempt. If after three attempts it doesn't ignite it locks out as it should, and I have to turn the furnace power off and then on again to reset it. Attempted fixes have been to clean the flame sensor which didn't help. Then we changed out the ignition switch which didn't help either. Next recommendation is to swap out the motherboard. Wondering if I am on the right track here or if I should try something else? Thanks!