u/OpinionSame2048

We are doing an entire kitchen renovation. The crew uncovered this duct in a wall between the kitchen and dining room. They are planning to look further into it tomorrow- but thought I’d ask here what it could be. There appears to be 2 small water pipes running through it and terminating in the bathroom above. However, the duct continues up into the second floor wall away from the water pipes. What do we think this is? It’s heavily protected by grates with some sort of lath and cement over it. The hot water heater and boiler are below, but they vent into the chimney which is about 30” away.

Thanks!!