whats the benefits of a chimney liner??
- Thread starter nnysnowbelt
- Start date
-
Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.
We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.
We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
- Status
Owen1508
Minister of Fire
Basically for improved performance and safety. If your Masonary liners are cracked, missing or damaged it would be cheaper to reline rather then re build. If you replace a stove and the chimney is oversized for the new unit it could improve draft It makes it easier to maintain/clean. Smoke shelves are sometimes missed.
I'm sure others will add to that.
I'm sure others will add to that.
And just brushing the gunk down into the stove and scooping it out instead of having to pull it out every time is worth the cost of a liner all by itself.
8ball
New Member
In Canada it's law that a solid fuel chimney must match the flue collar of the said appliance.The reason is to improve draft and to maintain flue temperatures.You can imagine a 6" wood stov pipe/chimney venting 300* temps up a 20' chimney at the bottom temp is 300* and at the top temp is probably 200*,now take that 6"/300* combo and vent it in an 8" chimney and most people can understand that the larger diameter chimney will rob heat from your starting temp of 300* an at the top of this chimney the temperature will likely be 125*.The hotter the chimney the faster the rise of heat up the stack,therefor creating stronger more reliable pull/draft on the appliance resulting in improved wood burning performance
This is very true but only applies to inserts which is not the norm here and in many other areas as well. If it is an insert then it absolutely needs a liner a free standing stove going into a properly sized clay liner that is in good shape can be a perfectly good setup. Although an insulated liner will definatly work better.
NewStoveGuy
New Member
Hmm. Would this mean if I have a chimney designed for a stove with an 8" flue (and with an 8" thimble) that I can't expect reliable draft performance if I get a stove with a 6" flue opening.?
It will probably be ok but it would be much better if it was 6" to match the stove.
I think 8ball gave a great explanation what will happen with an oversized flue. You will cope with the increased loss of heat and therefore draft by leaving your air control open more which will send more heat up the stack. However, you may never be really aware that you burn more wood than needed. The most noticeable differences will be during startup when you may experience problems to establish proper draft and at the end of the burn when the draft may not be enough anymore to burn down the coals. Lower flue temps also mean more accumulation of creosote and therefore higher risk of chimney fires. Sweeping the flue more often would be a good idea. What kind of chimney are we talking about here? Single wall, double wall ...?
It depends. Sometimes it will work out fine and sometimes not so good. If there is strong draft and the chimney is taller than the minimum and there are not a lot of 90 deg turns in the smoke path it may work out ok. For example, an 8" straight up, interior chimney of say 20 ft has a better chance of performing well than one that goesup from the stove 3 ft, then out the wall to outdoors and then up 12 ft.
NewStoveGuy
New Member
Not sure. It is a well built 16"x16" masonry chimney that extends 6 feet above the top of the thimble which is itself centered at about 3 feet off the floor. Once it goes through the ceiling it extends another 10 to 12 feet above the roofline. The base (which includes the thimble) is a 6.5' x 6.5' x 16" wall with cement exterior that retains heat and divides the living and dining room. It's got liner which I believe is ceramic or tile and I believe is also 8" but I'm not sure if its round or square. I'll check tomorrow.
Why that difference between stove and insert? Isn't a stove with a few ft of pipe connected to a masonry chimney not pretty much the same as an insert with a quick-connect?
8" flue in a 16" chimney means only 4" or one layer of brick at each side. Are you not usually recommending a full insulated liner in such a situation because there may not be enough clearance to combustibles on the outside?
yes and i should have said if it has proper clearances
The difference is that an insert with out a liner is not connected to the flue even with a direct connect it is still not really connected. In addition the flue for a fireplace will be much larger and be way over sized for a stove. A stove going into a chimney that was built for a stove with a crock and 8 by 8 liners can be connected properly and yes it is still a bit oversized but not nearly as bad as if it were going into a fp chimney with atleast an 8 by 12 or larger flue.
Thanks, that clarifies a lot. Not sure if I agree with the "bit oversized", though. A 6" liner has a 28 sq. inch area, an 8x8 flue 64 sq. inch or more than twice the area. Even if it would work without, I think it would still be a good idea to put a liner in there and we seem to agree on that.
i agree it would be much better to line it but we see lots of stoves going into 8 by 8 clay liners that work fine. i am sure they would be better with a liner though
- Status
