Lennox Hearth C160, CA160, SWI160 OPERATING TECHNIQUES AND HINTS, ACHIEVING CLEAN, LONG BURNS, GETTING THE MOST OUT OF YOUR FIREPLACE INSERT, MAXIMIZING YOUR FIREPLACE INSERTS OVERALL EFFICIENCY

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Recent developments in wood-burning technology have made wood-
burning a cleaner and more convenient way to heat your home. Overall
efficiency in a wood-burning appliance is a combination of combustion
efficiency and heat transfer efficiency. Whether heating your entire
home, or just a room or two, your understanding of how to best operate
your stove or insert will enhance its overall efficiency and performance.
What this can mean to you is longer, cleaner burns, less wood use and
more heat.
OPERATING TECHNIQUES AND HINTS
GETTING THE MOST OUT OF YOUR FIREPLACE INSERT
The following sections will outline techniques you can use to “get the
most out of your fireplace insert.” Please read them carefully.
It is important to know that for high, combustion efficient, clean burns,
you will need to have sufficient temperatures inside the firebox for
thorough combustion. The best method for determining if you have suf-
ficient temperatures is to watch the brick lining in your firebox. When you
first light your fireplace insert, the bricks will turn a dark brown or black.
After 20 to 30 minutes of a hot fire, most of the bricks should return to
near their original light brown or yellow color. This means the bricks have
reached a high enough temperature for your fireplace insert to achieve
high combustion efficiency.
Second and just as important, is achieving a high level of heat transfer
efficiency. Slowing the rate of flow through the stove or insert enhances
heat transfer, thus allowing more time for heat to be transferred into your
home. To do this, be sure to thoroughly preheat your fireplace insert and
then reduce the amount of primary air by closing the draft control (lower
left) to about 1/2 to 3/4 open. This will decrease the excess oxygen in
your flue, which carries heat up your chimney, but should still be enough
air to allow the fireplace insert to produce its maximum heat output.
(More air may produce a lightly greater amount of heat, but will greatly
increase wood consumption). When the area being heated reaches a
comfortable temperature, slow the burn rate by closing the control to
further improve heat transfer.
To get the most out of your fireplace insert, you will need to combine
good combustion efficiency with good heat transfer practices. The fol-
lowing are some tips on how to operate your fireplace insert to achieve
the highest overall efficiency.
1. Thoroughly preheat your fireplace insert before slowing the burn rate
by closing the draft control.
2. Measure the fireplace insert temperature at the hottest point on
the fireplace insert top or face. Use this information to repeat burn
rates.
3. Once preheated, add wood (if needed) and partially close the draft
control (lower left).
4. Operate your fireplace insert as much as possible in the low to medium
burn ranges.
5. Do not lower the draft setting so low as to completely extinguish the
flames in the firebox. Check for at least some small flames twenty
minutes after setting the draft control.
6. Do not continually operate your fireplace insert in the high (wide
open) setting. This wastes wood by carrying a great deal of heat up
the chimney and can damage your fireplace insert and chimney.
7. Go outside and check your chimney. More than a very small amount
of smoke indicates wasted heat, creosote build up and pollution.
MAXIMIZING YOUR FIREPLACE INSERT’S OVERALL
EFFICIENCY
To achieve long burn times, after having thoroughly preheated the
fireplace insert, let the fireplace insert top cool down to 275 to 400
degrees (on Elites, locate thermometer on the face of the insert just
above the door). Now load the firebox and set the draft control. At this
point, you may need to burn the fireplace insert with the draft open for
a few minutes to ignite the wood. All Lennox Hearth Products stoves
and fireplace inserts are EPA tested for emissions at low burn with the
air control completely closed. Whether or not you should burn your
fireplace insert with the air control completely closed will depend on the
following factors.
• How you load your wood
• Your chimney type, height and draft
• Your wood type and its moisture content
• The temperature of the fireplace insert
• Which model stove or insert you have
Experiment with different loading configurations to achieve longer burns.
Try loading the wood from side to side and nesting it in the ashes to prevent
airflow under and around the wood. Fresh wood should be loaded to the
back of the firebox or to the sides. Hot coals or half burned wood should
be brought towards the front of the firebox. The way you load your wood
can seriously affect burn times. If the new load does not ignite within a
few minutes, try crisscrossing the load to allow more airflow around the
fire, or try a slightly hotter fireplace insert temperature.
Determining the lowest setting for efficient low burns. This will require
some experimentation on your part. Try closing the air control all the way
with the fireplace insert temperature at 325 degrees to 350 degrees. If the
flames are completely extinguished, open the air control halfway and then
slowly close it until there is only a small amount of flame. It is important to
check the fireplace insert about 20 minutes after setting the draft control
as it takes this long for the fireplace insert temperature to stabilize. There
should still be some small flames on or above the wood load.
Use 325 degrees as a starting point. You can try starting temperatures
25 degrees higher or lower to achieve desired burn times, start 25 degrees
lower if the fireplace insert burns the wood too quickly or 25 degrees
higher if there are no flames in the firebox for more than a few minutes
after loading the wood. You may or may not need to burn the fireplace
insert with the air control open for a few minutes prior to setting the draft
for a low burn, this will depend on the factors mentioned above. Be sure
not to smolder a fire overnight. Check your chimney for large amounts
of smoke as this indicates very poor combustion.
It is important to realize that stove technology has changed. Stoves
and fireplace inserts have changed a great deal in the last few years. This
has led to substantial changes in the methods of operation in new stoves
as compared to older stoves. In old stoves without full brick linings and
ceramic insulation, the rule was “get the stove as hot as possible before
setting the draft on low for overnight burns.” On newer, high technology
Lennox Hearth Products stoves, this is not necessary. Although it is still
important to have the stove hot enough to burn efficiently, it will require
less preheating. Once you have determined your optimum operating
temperatures for various burn rates, we believe you will find your fire-
place insert an extremely convenient way to achieve your heating needs.
Do not reload the fireplace insert for long burns when the stainless
secondary tubes or baffles are glowing red, or when the fireplace
insert is uncomfortably hot to load. This indicates the fireplace insert
is too hot to load for a long burn. Also, do not load wood for a long burn
on a deep bed of hot coals. Try stirring the coals a few minutes before
loading the fireplace insert for a low burn to allow some of the unburned
coals time to burn.
ACHIEVING CLEAN, LONG BURNS