Gap between water heater and vent duct

[scattershot]

Today I noticed that there's about a 1.5" gap between the exhaust opening top of our water heater (tank, natural gas) in our basement and the metal duct that carries away the products of combustion to a vent on the side of our house.

Is that normal? By comparison, it looks like the vent duct for our space heater is fully attached to the heater body.

 

[Jeff Handy]

If there is a little oversized cap sitting on short metal legs on top of the heater exhaust, that then feeds into the exhaust vent, you are ok.

That air gap is to allow the rising exhaust gases to pull room air behind them, to help them “draft” or to rise up and out.

 

[SHEPLMBR]

PICTURES?

 

[Jeff Handy]

If the gap you are talking about is like this, where you can see under the cap that conducts the water heater exhaust into the vent going outside, then you are ok.

 

[Jeff Handy]

When the water heater is running for awhile, you can hold a lit match or lighter right next to that little gap under the exhaust hood.

If the flame gets pulled strongly into that gap, then your flue is drafting well and you are fine.