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Can you tell where the noise is coming from ? Does everything seem to be working?
I do not suspect it is something to panic over, but would have it checked out as soon as you can.Your furnace has several safety devices that will shut it down if there is any danger.
Without being there kind of hard for me t say what this is. If there is any way you could record a short video clip. I might recognize the sound.
Could be as simple as a loose vein , damper or something that is loose.