Weil-McLain AB-120 Combi noise

GML99

We have a 2 year old Weil-McLain Aqua Balance 120 combi boiler running on natural gas. We have fin tube baseboards. When either DHW or zone calls for heat I frequently hear a groaning, then repetitive machine gun sort of sound for a few seconds at first. You can hear it in this video between 6-10 seconds. It seems to be coming from the blower assembly. Any thoughts?
https://photos.app.goo.gl/LWWU6uWAocFZTNFz6

I'm not sure if it always made this noise and I just notice it more now or if it's actually gotten worse over time.

Thanks for your help!

GGross

I can't hear it on my speakers, I do see that they are using a similar style Venturi assembly to some other units I have dealt with. from your video it should be to the left of the pump, those have a little plastic flapper in them and I have seen them chatter quite a bit when there is a venting issue. I'll try to listen with headphones to see if I can hear it better but don't have any at the moment. If it is the venturi sometimes I have seen it caused by a venting issue, and other times by improper combustion setup. If it is a more electronic groaning sound I have seen that caused by restricted diverting valves, but that should stop before the unit fires, sometimes that vibration can be heard at a distance but usually it is just something you can hear right next to the unit and not usually while the cabinet is on

GML99

Thanks for the quick post! I saw another post here with a chattering flapper(air intake valve?) and it wasn't really the same sound as mine, and mine definitely has two parts. A groan and then repetitive tones.
Let me know if hearing it with headphones helps. It is sort of a low tone.