Water heater vent

[mathew stouffer]

Besides the good laugh would this effect the draft to the point where it should be corrected. I did not notice and back draft during the inspection.

[Gunnar Alquist]

Matt,

I think that needs to be deferred. If nothing else, the horizontal connections need to be corrected.

[David Bell]

Assuming that the furnace is induced draft it's vent should be located at the highest point available in the chimney. This would leave the bottom of the tee available for the water heater.

[mathew stouffer]

Good point. Plus check out the cool "U turn"

[mathew stouffer]

David,
Will pressure from the furnace vent cause backdrafting of the water hater vent if it is located above the water heater vent connection. Is that the reasoning?

[David Bell]

That is the idea, the power vented unit when installed above will actually increase draft when sized correctly.

[Ken Rowe]

Highest BTU appliance should always be the lowest in the stack.

Induced draft and power vented are two different thing. No other gas appliance should share the same vent with a power vented appliance.

Typically you're only allowed to vent two, sometimes three gas appliances in one vent. This appears to have 4 appliances.

Here in MN the lower BTU appliance must connect at 45 degree angles, 90s aren't allowed for them on shared stack connections.

Typically water heaters are only allowed 1 90 degree angle before connecting to the vertical stack.

I'd call it out for review and repairs.

[David Bell]

Pardon my mistake. I meant to say fan assisted.

[Bob Harper]

Keep in mind the difference btw good vent design practices versus code requirements. You can manifold multiple appliances and there is no fixed number in the codes. As long as the vent system is engineered for it, you can manifold a bunch of appliances.

You are allowed to common vent a fan assisted CATI furnace with a draft hood equipped water heater but it is not a good idea. Should the common vent become blocked or restricted, the furnace can vent out the WH draft hood without tripping any of the three safeties in the furnace.

The code states in one section to route the smallest appliance higher than the larger but you are allowed to manifold at the same level. The reason for this offset is primarily to allow for a greater vent rise off the top of the smaller appliance. It has nothing to do with one pressurizing the vent or some sort of staggering for baffling positive pressure flue gases.

You may have additional more prescriptive local requirements such as Ken mentioned about Mn. Again, just differentiate btw requirements versus recommendations.
Bob