I'm contemplating tearing down my chimney and putting in a zero-clearance stainless stovepipe for my oil-furnace instead;
All the stove/chimney/other flue systems I've ever seen have the pipe from the appliance go up, turn horizontal, and plug sideways into the chimney stack. Is there any reason why I shouldn't go straight up from the oil-furnace, through the roof? It's pretty much open all around.
--Goedjn
Do you mean exit exaust at roof level on a pitched roof with no raised chimney ? It wont pass code or work, you will get poor draw and downdrafts in certain winds
You need a drip leg under the stack. You don't want rain water going directly into your heater.
>All oil units are forced draught , Yea I never had one, ok I learned something,
Depends. The International Mechanical Code, what most areas in the US are using will still require a particular height above pitch for your furnace exhaust. You may find that that bright stainless pipe sticking so far up on the roof will be far worse looking than a chimney.
If you do it, check the local codes first. Read Mechanical Code section
804.3.5 BTW, drip legs are not to code, as section 5, of 804.3.5 clearly states. and this will also add an additional 15 to20 feet total effective length (TEL) to your exhaust, and as each make of furnace has a total length, you may find that you have exceeded this with a so called drip leg.Since you have what is called a forced draft system (oil) you will also have to insure that each joint is sealed properly. Code section 804.3.1
And I hate to look like I am busting on everyone that has replied so far, but Mark is wrong about the draft. Oil units are forced draft, therefore draw isnt an issue since the exhaust will be a positive pressure style.
If you dont mind, why are you considering this? I mean....most people do not want a mobile home style roof jack on their home.
Ok, does this drip leg need some mechanism for draining the water out, or is there little enough of it that it's expected to evaporate by itself? Looking at the retrofit chimney liner retrofit kits, there doesn't seem to be any such mechanism, just a cap for the bottom of the T. And with a rain-cap there shouldn't be very MUCH outside water. What code book covers the rules for this sort of thing? Is it buried somewhere in the building-code, or do I need to go find the mechanical code-book, too?
--Goedjn
Largely because my masonry chimney is loosing bricks, and I can't seem to get any professional to do more than come look at it and say "wow, that's bad"...
I may decide to just rebuild it myself, since the stainless metal chimneys, while easier, don't appear to actually be CHEAPER than a masonry chimney, except for the labor. And since it looks like I'll have to do it myself anyway, that matters less than it might.
Basically, at the end of this month, I shut the furnace off, cut a hole in the roof, tear down about 11' of chimney down through the attic, and staple a tarp over the hole. I then have until late october to get something up that costs me less than $7,000 and lets me run the furnace again.
--Goedjn
Not just water, but dead birds, squirrels, etc get in there You want to be able to clean it out in some manner.
I have no clue.
I don't know how much of it would be considered DIY, but could you learn to do brick pointing? Next would be a liner of some sort that goes down from the top. No that we know the problem, perhaps others have better solutions.
Also, depending local climate, and on how much of the flue runs through un-heated attic and above the roof line, you may get significant condensation inside the pipe.
I've seen quite a few homes that have metal flue inside with a decorative masonry "chimney" above the roof line. Don't know what code requirements are for this, but as long as you're going to have to look into your local code requirements anyway, it might be an option to consider.
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