Multiple Loud Bangs When Furnace First Comes On

Old 12-09-13, 06:51 PM
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Multiple Loud Bangs When Furnace First Comes On

We just turned on the furnace for the winter, and for the past week I keep waking up to loud bangs from it. We usually only run it in the morning, and these bangs only occur during the first time that it comes on, the rest of the day I don't hear anything as it turns on and off. It's about 10 bangs in a row almost like someone is inside the furnace and knocking on the metal. It scares me out of my sleep! What could this be? It's weird to me that it only happens the first time the heat comes on for the day.
Old 12-10-13, 07:27 AM
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You say "when it comes on the first time". Does this mean you are turning the furnace off for some period and it only happens the first time when you turn it back on? Or, does it simply mean it makes the noise during the night, waking you up?

Have you been down right next to the furnace when it turns on that first time to help pinpoint the source of the banging? I think first would be to determine if the sound is coming from the furnace or from the ductwork. It's possibly the metal expanding and "oil canning".
Old 12-10-13, 08:37 AM
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I have the exact same issue.
I have 4 burners and one of them is backfiring few times making loud banging noise until the burner finally lights up.
My thread is here:

I have furnace cleaning guys coming today.
Hopefully, that'll resolve the issue.

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