MANUAL DAMPER MAY BE INSTALLED BETWEEN BAROMETRIC DAMPER AND CHIMNEY
FIGURE 10 A BAROMETRIC DRAFT REGULA- TOR AND ITS INTENDED EFFECT
AIR DUCT INSTALLATION
SPECIAL AIR FLOW CONSIDERATIONS FOR WOOD/COAL FURNACES
With Wood/Coal furnaces, a special concern is pre- venting wood joists and flooring close to the hot air ducts and plenum from overheating. A fire hazard is created by the hot air flow circulating through ducts not designed for such high temperatures. Most Wood/Coal furnaces produce much hotter air than oil or gas fired units. So most clearances from the existing ducts and plenum are usually inadequate with a supplemental Wood/Coal furnace installation.
When installing the air duct, follow recommended clearances shown in figure 11.
The plenum on the Woodchuck should be 20"x23" and no less than 18" high while maintaining a minimum of 18" clearance to the ceiling or other combustible mate- rial. In a power outage situation, excessive heat buildup at the plenum top may be dangerous, so make sure clearances are maintained. For the Model 4000 allow at least 4" from ceiling to plenum.
The ducts, fittings, grilles and registers should be sized so that the total external static pressure does not exceed .02 W.C. inches while developing air velocities
With no draft in chimney, regulator is closed, no air gets in.
Moderate suction in chimney pulls regulator open enough to maintain desired draft for appliance.
Excessive suction in chimney pulls regulator further open, allowing substantial air into chimney connector.
of 600 ft/min to 1000 ft/min at the registers. NEVER supply less than 150 sq. in. of heated air outlet area.
Cold air returns must be at least equal in size to the heated air outlets and preferably 10% larger. Every Woodchuck furnace MUST be installed with a cold air re- turn.
ADD-ON INSTALLATIONS
Before installing your Woodchuck furnace, consult your furnace man and local state building codes to de- termine if your furnace will accept an
Once it has been determined that your existing fur- nace will accept an
Figure 13 shows a central installation.
We do not recommend supplemental wood furnace installations with series connection. These types of installation are not advisable in spite of their simplicity, see figure 14.
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