Is the loud metal clicking sound near your flue when the gas furnace runs a major issue or just an old electrical breaker popping off?
Asked by Roy Brunet 
6 months ago
Last Updated: May 12, 2024
I could use some advice. Just moved into my new house and I’m using the gas furnace for the first time. It’s up in the attic on the north side of the house. I keep hearing a loud metal clicking noise every few minutes when the furnace is on. It’s not coming from the furnace itself, but from the attic on the south side, near the flue. My electrical system is pretty old, but the furnace is new. It sounds like a breaker tripping, but it’s not. The HVAC guy checked the furnace inside and said everything is fine. It’s going to be really cold tonight and the furnace will be running a lot, so I just want to be sure it’s not a big problem. This house has been a nightmare since I moved in.
If it’s metal duct, it can generate noise as it warms up and expands. Especially if it’s secured too tightly to the wooden structure. To troubleshoot and locate the noise, try lowering the thermostat for 20 minutes, then raising it and heading into the attic to find the source. Remember to bring a flashlight and your phone to record the location of the source for potential repairs if necessary.
I forgot to mention, I recently had knee surgery and can’t go up a ladder. I really could use some assistance. As long as the noise is somewhat normal and not a fire risk – that’s what I’m worried about. I’m not used to dealing with gas in my house. And on top of that, there’s the issue with my 100-year-old electrical system acting up occasionally.
Melanie Phillips Brasuell it sounds like you’ve figured out that the noise is related to the heating cycle. It’s unlikely to be electrical noise because that’s usually sudden and loud, not happening regularly. If you can record the sound on your phone and share it, that would really help pinpoint the issue.
Hey there, I hear the sound you’re talking about. Sometimes it happens when the heat is on, sometimes not. It’s like every 1-3 minutes or so. I think it’s coming from above my bathroom where the AC unit is outside the window. In the attic, there’s just some ducting, I believe. The furnace is on the other side of the house in the attic.
Melanie Phillips Brasuell hey, it seems like the noise is caused by the damper in the ceiling grill moving quickly because of the air velocity and expansion from the heat.
Oh no, 😳 should this be left alone or is it time to call a handyman?
Melanie Phillips Brasuell’s effectiveness depends on how much you can tolerate. Swapping out the grill is pretty much the only solution, but they are all poor quality and flimsy. It’s doable as a DIY project… Just unscrew the current grill, take out the damper, then put the grill back in place
In my house, it does that gently as the metal warms up, it’s nothing to worry about
E ah!! It’s good to have that information. Appreciate it!
I apologize for the spooky vibes.
That’s what I’ve been worried about. 😅 But seriously, I briefly thought there might be an animal up there.
Metal expands when heated and contracts when cooling, resulting in loud pops either way. If you’ve ever placed a cold baking sheet into a hot oven, you’ve likely heard this sound.
My hot water pipes are making popping and clacking noises, haha!
Our floor has gas furnaces too, and they behave similarly.
Maybe it’s just a switch in the control panel. I’ve noticed my older furnace makes a clear clicking sound when it’s powering on and off. It also clicks when the circulating pump kicks in and shuts off.
Mentioned that the source of the noise is quite a distance from the furnace.
Melanie Phillips Brasuell said the noise might be originating from a control panel that is not necessarily located in the furnace.
Oh, got it! I’ll also have someone check that out. Thanks for the heads up!
Melanie Phillips Brasuell Well, without knowing the system, it could be an inline fan, expanding metal ductwork, water pipes banging, or water hammer from a pump turning on/off. There are a lot of possibilities to consider.
Hey, so I had a HVAC guy come out, but he really wasn’t much help. Do you have any suggestions on who I should hire to possibly figure this out? It’s starting to drive me a bit crazy because I just can’t ignore it.
It seems like the ducts are expanding against a mounting bracket. You’ll need to locate the exact spot, adjust by loosening or tightening or adding padding, and it should solve the issue. In our previous home, this was simple because the ducts were exposed in the basement ceilings. I just placed a sock underneath the clanking bracket.
I’ll have to see if I can get someone to make the trip for me!
Melanie Phillips Brasuell if you happen to be in Vancouver I can give you some recommendations 😉
Oh wow, I’m all the way in Arkansas US- that’s quite a distance!
Haha, my pipes make this noise when hot water is flowing through them.