Chimney venting to outside from the bottom/underneath???

RickT

Does someone have any idea why one of the chimneys in my house has a duct/vent connected to the bottom of it running all the way to daylight? The round metal duct goes all the way across the kitchen crawlspace to the exterior, doesn't branch anywhere else.

This is the chimney that vented the original kitchen gas stove (all the fireplaces were gas, too- they were wealthy; most stoves in the 1890s were still wood!). Currently the only thing it vents is the oven hood. The duct doesn't look to me like it's original, though. It's definitely not 100 years old.

I would like to remove this duct because it is bringing cold winter air into the crawlspace. Makes the floor very cold over the leaky duct. Will I regret it?

STEVEusaPA

It must be there for a reason. Better show some pics so we can identify it.

Fred

What diameter is the duct? It's probably there to vent the range/oven hood. Probably because they didn't want to run it up and penetrate the roof (if they had a convenient way to get to the roof). Is this a 2 story home? I assume the range/oven isn't on an outside wall? That would have made it easy to vent out the side of the house without opening the kitchen ceiling and maybe even the ceiling in another room for ductwork.

RickT

It's big. At least 8 inches.

I was assuming the hood vents into the chimney only. Wouldn't that be the way they'd have done it?

I took the hood fan partially apart and of course can't see into the chimney- but a rigid wall pipe goes up and makes a 90 turn into the chimney wall.

Yes, electric range is on interior wall.

I'll try to get a picture that shows something.

Fred

If you are willing to lose the exhaust venting from that hood, you should be able to remove the pipe.

Jamie Hall

The real question, seems to me, is whether or not the chimney is continuous through the pipe and open at both ends to the rest of the world -- and that isn't clear here. It shouldn't be all that hard to find out...

Which doesn't answer the question as to why the pipe is there, but would be kind of useful to know.

STEVEusaPA

Why not put the fan on and go outside and see if air is blowing?

Aldousstone

Its the cokd air intake for your fire place. When your fire place is in use it pulles air directly from the outside into the fire box instead of pulling air from your home whuch in turn creates a draft. If the intake is blocked durrig use the fire place will still function however you will notice a draft, and there is a far greater potential  harmfull gasses willend  in our home. For example you have a roaring fire its and its really cold outside. You are cooking dinner and you have the hood vent running above your stove. Someone i in the bathroom taking a shower and have the fan on. Then the heater kicks in and all the suden the negative airflow going up and out your chimney is pulled down reversing the air flow and fills your home with smoke. Next thing you know you cant breath because the smoke is so thick and your girlfriend runs from the bathroom wi shampoo in her hair freaking out about finding her grandma's cat while smoke billows from your windows the fire alam is blaring and as you stick your head out of the window to breath you notice all of your neighbors all calling the fire deparment. One week after moving in. It took months to wash the smell out of the house. If you want it closed while not in use install a damper. It does hqve a purpose. And it does what its intended to do. You will notice a drastic increase in efficiency if used correctly.  

neilc

it's like you been there, done this