Hello,
Can the vent pipe (flue) for a gas stove have 2 – 90 degree bends in it?
I’m planning to have a gas stove put in adjacent to an interior support wall; directly above that area is the upstairs hallway. So what I was thnking was to come straight up with the flue, turn at 90 degrees (near the ceiling), then back up and go up through a closet.
Can these types of systems (gas) handle the double bend?
what about for a wood stove? Seems like the pipe should never be flat so there is no place for ash … to settle. (perhaps 2 45 degree bends)
Thanks,
Roger <><
Replies
bump
Not a plumber/gasfitter so I can't tell you code, but, it seems it would depend on how far the 90* elbows stay horizontal before vent gases build up...
Yes, it can, but I'll qualify that answer. In a gravity vented system, the height of the flue vs. the resistence of the flue have to be considered. Many, many stoves are vented like you describe and work fine. There some tables of rise and run etc, available from some of the vent pipe/system manufacturers, such as Hart & Cooley.
Timbo is right about formulas, but here are some basics - and things are different for gas vs wood. The gas requires a "B" vent flue and rthe wood needs an "A" aplication
Every 90° elbow will reduce the draft by roughly fifteen percent. two is OK generally
in an ideal diameter sized flue ( relative to the appliance requirements) you want a minimum fourteen feet of stack height to create a self ascending draft flow. A taller flue will increase the natural draft, up to a limit that most residences never reach
So if you are going past a seciond floor, the attic, and three feet above the ridge, you obviously have enough extra height to overcome the restrictions of the elbows, if theyare near one another. A horizontal run creates problems other than soot settling there. It will restrict flow drastically.
the thing that alarms me is that when both Qs are asked together is that someone might be contemplating mixing both gases in one flue - a big NO-NO.
The other problem can be - let's say that there is a masonry chimney in the house that was built for a fireplace, with a 12" x 12" flue. Then a fireplace insert was aded to improve the efficiency of the fireplace. The chimney then never got cleaned - because it can be harder with some of these than with wood stoves.
Then somebody comes along and decides that since the wood stove only needs an 8x8 flue, there is extra capacity for waste gassess from another appliance such as you have. So they add a port to the chmney on the other side of the stck. Now they are not only mixing gases in a flue lined with nasty creosote and all ready for the annual chimney fire, but they discover that the gas heater is so much cleaner and easier, so they give up on using the wood stove altogether.
um-hum...
Now, they have an appliance that only needs a stack of 3"or four inch diameter taking off into a voluminous space that was 12" x 12". Think there are any chances that those CO fumes will rise to the top and spill out over onto the roof?
Not without a rather large fan or an after burner to create a draft. The ehaust fumes will merely linger in the stack, cool quickly, and find a way to leak back into the hosue, a the cleanout in the cellar or at the fireplace insert. Then, they will make somebody sick or dead. probably sick and it will get blamed on the fluy, while the resiodents blame their mental confusion on advancing old age.
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Hello piffin and others,
Thanks for your advice. What happend was that I got convinced by the guy who sells ventless gas stoves that this was a good idea. I have since found out that ventless gas will be trouble due to moisture, caustic vapors, CO2, ... . So now I still want the gas stove, but go with a vented stove. The location for the stove is situated along and interior wall that has a hallway directly above it (not enough room in the hall for a chimny chase). So what I need to do is elbow it back up near the ceiling then up through a closet, then through the roof; total height will be about 24' (34' wide single story house (sort of a cape with a finished upstairs) with 10' ceiling downstairs and 12/12 roof pitch). This would put a 4-5' horizontal pipe about say 7' above the 1st floor level. From what I'm hearing, this amount of bend should be ok. What I'll do is get the installer to check out the idea and work out the drafting/venting details. Then try and figure out how to hide the nasty flue pipe (or just live with it).
Thanks again,
Roger <><
Are you going to install it or have it installed professionally? Either way actually it will come with instructions that include just the information you are asking about. Vermont Casting aka Majestic has the info online using adobe.
" Then try and figure out how to hide the nasty flue pipe (or just live with it)."just hang your underwear over it for fast drying. You know how nice it is to step into warm undies first thing in the moirning...LOL
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