Okay, I have a funny question to ask of any heating and cooling

[ScreamingMeemie]

experts around here. For the past couple of weeks there has been a clunking and thunking in our ducts. (the same ones we got cleaned :))
It is so odd sounding, the first time it happened I thought there was someone or something in our basement. I can tell where it is coming from. It is in one of the ducts nearest the furnace. I also thought maybe a critter got in there, but it's only one spot and when I put my hand on it while it's clunking, there is no vibration like one would get from movement. So my question, What could be causing this, in only the one spot?

Thanks, Laura

[trof]

1. type of heating system?

[ScreamingMeemie]

3. Gas forced warm air.

4 years old.

[eyesroll]

2. Does it thunk right when the heat cuts out?

Ours does that. The heating guy said it's just the ductwork expanding and contracting with the furnace cycles. Totally normal (especially in old houses with old ductwork.)

[ScreamingMeemie]

4. Thanks. Does it do it in just the one spot for you as well?

It is very creepy sounding. Especially after one stays up watching "In Cold Blood". Thanks eyes. :)

[eyesroll]

7. I think it's only one spot

It comes from right under the living room, so I'm assuming it's just one duct (or perhaps where two join together). Thunk.

[underpants]

5. Heat engineering team of monkeys

I had the same thing at my last apartment. It really sounded like someone was banging wrenches against the pipes. That was a really old building though.

Four years? Hmmmm it could just be the ductwork contracting and expanding as stated above.

[ScreamingMeemie]

6. Yes yes yes!!! That's exactly what it sounds like. That and a

far off door being closed. This is the first year it's happened after four years of living here, so it was a little startling in the middle of the night. Thanks!

[eyesroll]

8. Did it start right after the duct cleaning?

Ours didn't start doing that until it died in the middle of the night and the heating guy put it on "emergency heat" until a part needed to run it correctly came in. After that, it started banging, and it didn't stop. The heating guy said sometimes changes to the HVAC system trigger the banging (different airflow, etc).

[ScreamingMeemie]

9. Yes about 3 or 4 days after, that I noticed anyway.

That could explain it. He drilled little holes into the duct work and then plugged them. This particular duct, he drilled a hole in and cut a 10x10 square and then patched it. I bet that is it.

Thanks eyesroll! :)

[underpants]

10. It was my running joke

Apparently there is a lot that can cause this. eyesroll cites just such and example.

[Don_G]

11. You Can Try Something

Get a piece of nylon strapping and use it to replace the hangers nearest the noises. It will flex a little with the expansion and contraction of the ducts and prevent the sound transmission through the floor and joists.

[Robb]

13. this is great advice

(like you need me to say that).... if you can get in there, this will work on all kinds of things, including hot water pipes that clang. :)

[ArkDem]

12. Whatever you do don't read The Exorcist.

.