Class A Chimney, Exits Below Grade

i am back in action and will be installing a new yorker wood boiler, not the Harman boiler that was likely to be delivered some time in 2010. anyways....i managed to poke through my 24” stone foundation, one big hard stone left and my hole will be complete. now, heres the deal. the chimney exits the house, below grade. I planned on basically pouring a big concrete box (think window well) around the pipe, big enough for access to the cleanout. what I didnt realize, is just how far below grade this whole deal actually is. this is gonna be a pretty deep hole, and awkward to access the cleanout. so the million dollar question is, can I put my cleanout tee on the inside of the house, with just a 90 degree elbow on the outside? then my second question is, if I do that, how do I support 24’ of chimney that way?

Here's the ways the pro's do it. (clean out below thimble)

i'm using class "A" metal chumney.

ssupercoolss wrote:i'm using class "A" metal chumney.

Oops!

(I knew I should have learned that "Reading" crap better!)

Can't you do something similar with a metal chimney though (separate cleanout below thimble?)

well, I am open for options, but the cleanout below the pipe like you have there would be a pretty tough one. my foundation is stone, and I am having enough trouble just getting a hole for the pipe. I am just kind of wondreing now if I could run a flexible chimney liner through the wall, 90 degree up, and concrete the whole thing in, then adapt to my class A chimney. I am hoping to get a few more options before doing it all in class A with my tee outside.

Sounds to me like cleaning out through a tee isn't going to be an option. It will be a matter of disconnecting the stove pipe at the thimble and vacuuming out the bottom of the chimney. I think I would still use a tee so it would have the bottom for ash to build up and not set in an elbow. That would just speed up the buildup of ash in the horizontal section of the stove pipe.IMHO.

I have a chimney that sits on a stone foundation wall. The chimney was installed at least 40 years ago. It's about 33' tall and is below grade. There is no clean out, just a bit of a depression in the bottom where soot accumulates. It had been used for oil fired heating until about 2 weeks ago. Now it's coal fired!

A tee was installed on the Keystoker boiler with a cap for clean out towards the boiler, then there is a vertical section of pipe connected to another tee with a clean out cap and is connected to the chimney with a 2' section of pipe. I intend to clean to the bottom of the chimney with a shop vac through the upper tee.

Why not install a masonry chimney below grade and then, if you want it, transition to the class A chimney at or above grade? Most Class A chimney manufacturers provide parts for the transition from masonry to class A. The masonry portion of the chimney would provide the necessary support.

Machinist wrote:I intend to clean to the bottom of the chimney with a shop vac through the upper tee.

How about that idea? Have your thimble go into a "T" & then just cleanout the ash below the "T" with a vacuum....Just one hole through your wall,.