Tips and Techniques
for wood stoves
How to
"bank" a wood stove?
How do you
"bank" a wood burning stove so it will burn throughout the night?
Sara
Hi Sara,
Banking is an
old term that dates back to the days of cast iron stoves with leaky joints and
no gaskets on the doors. With little control of the rate of combustion, users
had to use devices like flue pipe key dampers (which we shouldn't need to use
any more) and place large unsplit, and sometimes unseasoned 'blocks' of wood at
the back of the firebox in an effort to extend the burn. These were the days
when a wood stove would deliver a net overall efficiency in the 25 - 35 % range
and banking was necessary to get them to burn more than a few hours without
reloading.
Things have
changed. New stove models are roughly 70% efficient, have glass doors that will
stay clear for a week or more of full time use if the stove is operated right,
and these stoves will easily burn over night while still producing a nice
flaming fire. Smoldering is no longer necessary to get an overnight burn.
It is still
useful to load a stove carefully to get a long burn. It helps to place larger
pieces more compactly in the firebox, because they break down more slowly that
way.
If you can't
get an overnight burn with a modern wood stove, then it is probably too small
or something is wrong with it. If you are trying to use an old stove, I would
strongly advise you to save up your money and plan to replace it as soon as
possible. Using old stoves is frustrating and wastes a lot of wood.
John
Fireplace doors open
or closed?
I have looked
over your site and didn't find an exact answer for my question. Should you
close the glass door of your fireplace when burning a fire or should you leave
them open? I have heard arguments for both sides. I heard that leaving them
open you draw out more heated air then you gain from a fire and on the other
side of the coin when leaving them shut you seem to not get very much heat from
a fire. Please help. I have wondered about this for years.
Ron
Hi Ron,
Yes, that
argument has gone on for a long time but the reality is it doesn't much matter
whether the doors of a conventional fireplace are open or closed, it will work
poorly either way. With doors open you get direct radiation from the fire, but
the warm air is sucked up the flue and the fireplace is vulnerable to smoke
spillage into the room.
With doors
closed, the normal tempered glass blocks almost all the direct radiation, but
the doors do reduce air consumption and susceptibility to smoke spillage. I
would recommend operation with doors closed, but then you risk shattering the
tempered glass.
There is no
good solution. We recommend putting an EPA certified fireplace insert into the
fireplace with a full stainless steel liner to the top of the chimney to make
the fireplace efficient, safe and more pleasant to use.
John
A little nervous about
wood heating
I have just
moved into a house in a rural area where the power goes out frequently. The
house has a wood stove. I am concerned about the safety aspects of using it as
the only heat source during power outages. Can I let it burn constantly for
days? Is it safe to leave it burning while I am sleeping or out of the house?
Does it give off carbon monoxide? How do I know if it's time to have the
chimney cleaned? I have been checking it with a mirror but don't know what the
indications of creosote build up are. Should I burn the wood slowly or fast?
Should I shut the damper and vents before I go to sleep? Any info you could
send me would be greatly appreciated. Thank you.
Hi,
The first thing
you need to do is find a qualified person, like an experienced chimney sweep or
stove installer, to come and clean the system thoroughly and inspect it. All
you need to know is if the unit and chimney are installed exactly according to
safety codes. If they are and the stove and chimney are in good condition,
then:
·
you can use it as your only heat source
·
you can burn hot fires constantly if you
want without fear of fire, although continuous high firing can damage the stove
·
you can burn it over night and while you
are away as long as you run it carefully and make sure the door is securely
latched
Your sweep can
advise about creosote build up once he sees the system. You can find good
firing instructions in our Tips section. In terms of building an extended fire,
the idea is to maintain flaming combustion. Do that and you can't go wrong.
John
A little confusion and
bad advice about flue dampers
Hi.
I found
woodheat.org to be quite full of information. My first wood stove has been
installed, and I'm not sure how to use the flue damper and air inlet supply on
the stove. What is the purpose of the damper and how should it be adjusted
during various burn times? How does the stove's fresh air supply and the damper
work in conjunction? For instance, if one is wide open should the other be, and
vice versa?
Look forward to
your response,
Rich
Rich,
I don't know
what stove this is, but operating instructions are usually provided by
manufacturers and those should be your main resource. In fact, we don't
recommend the use of flue dampers, unless what you have is a bypass damper that
is part of the stove. But I don't have enough information to help you much.
John
Rich replies:
Thanks for the
response. The stove is a Waterford Ashling Woodburning stove. It is set up with
a rear horizontal flue. Approximately 14" from the flue spigot flange is
the damper. The store I purchased the stove from included the damper. I just
assumed this was the correct procedure. As a matter of fact there is no mention
in the owner's manual about using a flue damper, only the primary air settings.
This seems to support the statement -"we don't recommend the use of flue
dampers". Why should I not be using the flue damper? A friend has beaten
into my head that the flue is critical in controlling the amount of heat the
stove puts out. He said if there is no damper or the damper is opened all the
way, the heat just goes up the chimney. The Ashling has a 'top air duct
assembly' and a 'top plate' with (for lack of proper verbiage) baffles. My
interpretation of this design is that these two items are to collect and
radiate the heat built up in the firebox. Yes, No? I am very surprised that a
wood stove store would promote the use of key dampers.
Rich
Rich,
A flue pipe key
damper should only be used when you can't control the rate of combustion from
the front end using the stove's combustion air control. Key dampers are
associated with various forms of smoke spillage into rooms, the simplest being
when someone opens the loading door without first opening the key damper. But
key dampers are also implicated in cases in which, as the flue temperature
falls towards the end of a burn cycle, draft collapses and the restriction
offered by the key damper can produce a condition in which the easiest path for
exhaust is out through the combustion air control or any other leak or opening
in the appliance. This is not very common but it does happen with cooking
ranges or sidedraft wood stoves with rear exit flue collars, for example. The
rear exit on your stove makes this a possibility.
Key dampers are
only acceptable for non airtight appliances, such as old cast iron
"non-airtight" box stoves. Flue pipe key dampers restrict flow even
when open, provide a place for creosote to build up and make the flue pipe
harder to clean. Your friend has expressed the conventional knowledge related
to key dampers; that they prevent heat from being lost up the chimney. But what
counts is the rate of flow of gases through the system. The faster the flow,
the lower the heat transfer efficiency. If you can slow down the flow to give
time for heat transfer, it doesn't matter how you do it. It is incorrect to
think that only a damper downstream of the combustion chamber can 'keep the
heat in'. By controlling the amount of air allowed into the fire with the air
control, you have only one control to manage and you don't suffer any of the
downsides to key dampers.
I'm not
familiar with the Ashling so I can't comment on the fancy terms used to
describe its innards. It could be that the first is just to keep the door glass
clear and the second is to improve combustion and heat transfer. Most modern
stoves have these components, but some manufacturers like to dress them up with
fancy terms.
John
Rich replies:
Thanks for your
help. It's interesting how some stores are in business only for the buck. The
store I purchased the stove from never asked about the original flue, nor
fireplace. They simply stated 'buy this, that and that, and we'll install it'.
After a bit of research I opted not to listen to them and had a chimney sweep
install a double wall solid pack chimney. It cost more monetarily, but provides
greater safety and peace of mind. I appreciate your response to my questions,
and will control the burn rate using the stoves intake only and leave the
damper wide open.
Thanks, Rich
A backpuffing
woodstove
I have a fisher
baby bear woodstove. It has one draft knob in the center of the stove. I have
been heating with this stove for five winters. This year I have noticed
considerably more backpuffing of smoke around the air draft knob, especially
when I am first building a fire. Generally once I get the stove to settle down,
I don't have any more trouble. Do you have any advice on how to remedy this
problem. Any help would be greatly appreciated. Thank You, Sam
Sam,
The backpuffing
you describe is usually caused by ignition of a build up of combustible gas in
the firebox. It means there is too much smoke and too little combustion air.
When transient conditions produce rapid ignition of the smoke, the resulting
increase in firebox pressure produces the puff. Low draft and a smoldering fire
is often the culprit. You might want to have the chimney and fluepipe checked
to make sure there is no obstruction limiting your draft. If the chimney is
clean, you could probably solve the problem by using more paper, more pieces of
smaller drier kindling and built up to heavier pieces more slowly. The idea in
getting a fire going well is for combustion to be bright and turbulent right
from the time you light the paper. Let the stove get good and hot and wait
until the wood is thoroughly charred before turning the stove down at all. It
is almost impossible to have a backpuff if combustion is bright and hot. By the
way, one good way to avoid smoldering at start up is to use the topdown fire
building technique, a description of which you will find in our Tips section.
John
How to start a
fireplace
I have the old
fashioned fireplace that is not a gas fireplace. I am having trouble lighting
it and keep it lit. What is the best way to start a fire that will last for a
long while. Thanks, Brendie
Hi Brendie,
The key to
starting a fire is to make sure the wood is dry enough and is split up small
enough to ignite. Problems starting and maintaining fires usually have to do
with dryness and piece size. Small pieces light easier than big pieces so use
about 10 pieces of finely split dry kindling. Use several sheets of newspaper
to ignite the kindling. The successful ignition of a wood fire starts with the
newspaper and progresses steadily to larger and larger pieces until the full
sized logs ignite. You'll find more information in our section on tips and
techniques.
Beyond that,
you'll need to practice. I'm still practicing and I've been heating with wood
for 35 years!
John
If it's gross and
bothersome, something is seriously wrong!
We heat with
wood in my house and I find it warm yet it's smell is gross and bothersome.
You are in
serious need of professional help. There should never be the smell of smoke
inside a house. Good systems NEVER spill smoke inside. Contact a chimney sweep
or experienced retailer to get the system inspected and corrected. Your health
and that of your family are at stake.
John
No comments:
Post a Comment