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BACK-DRAFT
There are two main causes of chimney downdraft. One readily recognized is air currents being deflected down the
chimney by nearby higher objects, such as a tree, building or a hill.
The other cause, equally or more common, but seldom understood or recognized, is that in many chimneys the flue
gases are chilled too quickly as they pass up the chimney. The temperature of the flue gases drop, they become heavy,
and then other gases from the wood fire have to push a heavy column of air ahead of them in order to escape up the
chimney. This often results in back-puffing or backpressure, odors in the house, or poor combustion, which can be
annoying. Remember, the hotter the air in the flue, the stronger the draft. Any air entering the chimney, which has not
passed through a hot fire will cool the air in the flue and spoil the draft and aid in the formation of creosote.
BACK-PUFF
Back-puff is the sudden ignition of gases within the heater, which happens when air is suddenly admitted. This is
because the combustion rate in an airtight heater is air Iimited. Air for combustion is regulated by the primary air
manifold and the thermostat.
If air is suddenly admitted to the firebox by opening the loading door, air will rush in and the gases will ignite. The
combustion surge of the gases is so quick that the resulting pressure can force the hot gases out any available opening
such as the loading door. Therefore, be cautious! Open any door or opening on an airtight heater very slowly and only
then after being certain the thermostat door on the heater is open.
The possibility of back-puffing is one reason that children or anyone who is unfamiliar with the heater should be
cautioned about touching the heater.
ASSEMBLY INSTRUCTIONS - NS220 (Newmac Status)
1.
Remove shipping carton.
2.
Remove top of unit with louver.
3.
Place firebox of heater on floor.
4.
Open loading door - packed inside of heater firebox are legs, bolts, nuts, floor protectors, knob.
5.
Turn over base legs down,
6.
Place heater firebox on base plate and line up with 2 holes at front,
7.
Secure heater firebox at front with 2 bolts and lock nuts.
8.
Attach 2 clamps at back of unit to bottom base plate
9.
Place louvered top onto heater firebox.
10. Install knob on lift top.
NOTES: Make sure all attached components are securely tightened to the base legs - firebox to base and clamps at
back. Check operation of loading door to be sure it locks tightly when closed and forms good seal with firebox.
BASE ASSEMBLY - NS220 (Newmac Status)
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