Why is this ok?

This diagram, taken from an ashi reporter article, is from simpson dura-vent and an example of an acceptable configuration for common venting of a hwh and furnace.

It has always been my understanding that the hwh (if lower btu) must enter the common vent above the furnace. Is this not the case?


It does in the diagram I’m looking at.

Ah, so if the draft hood of the hwh is higher than the furnace collar, it can join the common vent anywhere? That doesn’t seem right.

Think I found the answer.