Vermont Castings Merrimack Homeowner's Installation And Operating Manual page 10

Merrimack Large Insert
automatic Setback control
The automatic setback air control is used when starting or
reviving a fire and provides an increased flow of combustion
air to the fire until the firebox is sufficiently heated. This air
supply automatically resets to the desired air setting, taking
the guesswork out of operating the stove.
Figure 9 shows the automatic setback control. Move the
primary air control lever all the way to the left. Push the
primary control about one more inch to the left to open the
air shutter (the lever will spring back automatically when
released). The shutter will remain open only if the stove is
below its proper operating temperature. Once open, the
primary air control lever may be adjusted to any desired
position. Once the stove heats up to its proper operating
temperature, you will here a clicking sound confirming the
shutter has closed. This returns the stove to the output
setting of the primary air control.
This feature is primarily intended for reloading the stove
when lower air settings (low heat output) are desired, but
it is also useful any time the firebox is too cool for proper
combustion or when freshly added wood does not ignite
readily.
For maximum efficiency and performance, the Merrimack
insert should always have visible flames in newly added
wood, either within the fuel pile or near the roof of the
firebox. Wood moisture, piece size, draft, weather and
firebox temperature will all have an effect on how quickly
flaming occurs. The automatic setback air control is a
convenient feature allowing more user flexibility and ease
of operation.
burn only high-quality wood
The Merrimack Large Insert is designed to burn natural
wood only; do not burn fuels other than that for which it
was designed.
You'll enjoy the best results when burning wood that has
been adequately air-dried. Avoid burning "green" wood
that has not been properly seasoned or cordwood that is
more than two years old.
The best hardwood fuels include oak, maple, beech, ash,
and hickory that has been split, stacked, and air-dried
outside under cover for at least one to two years.
For areas that do not have a supply of hardwood, com-
monly burned softwoods include tamarack, yellow pine,
white pine, Eastern red cedar, fir, and redwood. These
too should be properly dried.
Your Merrimack Large Insert will accept wood up to 22" (559
mm). Longer wood pieces work better than short ones.
Wood should be stored under cover to maintain dryness.
Even for short-term storage, however, keep wood a safe
distance from the heater and keep it out of the areas around
the heater used for re-fueling and ash removal.
10
Use the air control Settings
that work best for you
No single air control setting will fit every situation. Settings
for each installation will differ depending on the quality of
the fuel, the amount of heat desired, and how long you
wish the fire to burn.
The control setting also depends on your particular "draft,"
or the force that moves air from the stove up through the
chimney. Draft is affected by such things as the length,
type, and location of the chimney, weather, local geography,
nearby obstructions, and other factors.
Too much draft may cause excessive temperatures in the
Merrimack Large Insert, and could even damage internal
components. On the other hand, too little draft can cause
backpuffing into the room or a very sluggish fire.
How do you know if your draft is excessively high or low?
Symptoms of too much draft include an uncontrollable
burn or glowing-red cast iron. A sign of inadequate draft is
smoke leaking into the room through the stove or chimney
connector joints, low heat, and dirty glass.
In some newer homes that are well-insulated and weather-
tight, poor draft may result from insufficient air in the
house. In such instances, an open window near the stove
on the windward side of the house will provide the fresh
air needed.
When first using the stove, keep track of the settings of
the air controls. You will quickly find that a specific setting
will give you a fixed amount of heat. It may take a week
or two to determine the amount of heat and the length of
burn you should expect from various settings.
Most installations do not require a large amount of combus-
tion air, especially if adequate draft is available. Do not for
any reason attempt to increase the firing of your heater
by altering the air control adjustment range outlined
in these directions.
Use the following primary air control lever and fan speed
control lever settings as a starting point to help determine
the best settings for your installation.
Merrimack Large Insert control Settings
primary air
burn control
Rate Setting
High Fully left
Medium 1" from
full right
Low Fully right
air circulation
Fan control
Speed position
High Horizontal
Low Turn clockwise
Off Turn counterclockwise
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