VIII.4 Pellet Fuel Quality
Page 35
1998-2006 Edition
Ashis the typical residue of a pellet fire and a certain amount is expected. The ash, typically less than 2% by
weight, is normally eliminated from the appliance in two forms. The first form is "settle", this being the fly ash
which settles into the ash pan area or on the horizontal surfaces near the firepot (grate). The second is "airborne"
and is captured in the ash pockets and heat exchanger compartments.
The characteristic common to both is that they leave the firepot with the flame (vertically). They do not collect
inside the firepot in any significant amounts due to the "forge" effect. Additionally, neither form creates
appreciable deposits on the glass and both are relatively easy to remove.
Fuel containing more than 2% ash by weight will, depending on other variables such as burn intensity setting,
leave clinker deposits of non-combustible wood sap, ash and dirt below the incoming fuel and obstruct the air
flow necessary to properly expel ash products from the firepot. If this condition persists, the volume of
accumulated clinker below the incoming fuel increases and, ultimately, closes off the air flow completely. This
eliminates the forge effect resulting in the extinguishing of the flame due to the lack of oxygen. Before the fire is
extinguished, however, soot will deposit on the glass and the interior of the entire unit and the exhaust system.
Moisture Content: Another significant factor is the moisture content of the fuel. As you are
undoubtedly aware, moisture not only "dulls" any fire, it also promotes the collection of burn products on exhaust
systems as well as in the ash collection chambers and shelves. It also causes a "crusting" of these burn products
and increases the cleaning and maintenance effort required.
Pellet Size is yet another issue. The "actual feed rate" will vary depending on the size of the pellets. In
general a 1/4” (6.35mm) diameter pellet will feed faster and at a greater rate per hour than a 5/16" (8mm)
diameter pellet. The result is a hotter fire and a shorter hopper fill cycle. Additionally, the air to fuel ratio will
require adjustment accordingly.
The problems encountered due to poor quality fuel include rapid smoking up of the glass, rapid ash or clinker
accumulations in the firepot, creosote type accumulations on the glass and in the exhaust system and visible
smoke at the rain cap even after the unit has warmed up. If these symptoms are common, switch to a different
brand of pellets.
Do not burn cornor pellets made from any raw material other than dried wood. Pellet quality varies
widely from one pellet manufacturer to another. A good rule of thumb is that if it doesn't meet your criteria after
having tested them yourself or you are at all in doubt about the quality of the pellets, don't use them.
Contact your local Jamestown Dealer for information and recommendations on the best fuel available in your
area.
(Clinkers are a formation of clumps of fused ash.)
To Next Page
Loading...