Troubleshooting guide

Page 15
Assessing Performance Characteristics
How pellets perform from the hopper to the ash tray is the true test of the quality of a pellet. The
following are characteristics important in determining quality of a pellet.
1) Feed Rates: Pellets approximately ¼ inch in diameter, ½ inch long, free from fines, that
have a slick coating and are dry and dense, feed faster and more evenly than pellets not
having these characteristics.
Pounds of pellets fed per hour can vary up to 50% on the same settings, due to differences in
pellet quality. When pounds fed per hour vary at the same settings, so does the BTU output
vary.
2) Clinkers: Clinkers can only form from the minerals in the wood. Minerals, principally silica,
when melted by high firebox temperatures, can fuse into clinkers. Clinkers can be of the
hard, slick, glassy type or a more porous type.
Temperatures at which clinkers will form in the burn box will vary based on the type and
percent of minerals in the pellets. Pellets that clinker have been considered unsatisfactory for
residential wood pellet heating. However, St. Croix's Versa Grate System allows the burning
of a much wider range of pellets than other top fed pellet stoves.
3) Ash: The type and amount of ash can vary greatly in pellets. Some ash may be light in
weight and easily blown out of the burn grate. Heavier ash may pose a removal problem and
if not manually removed (several times daily in some cases) will plug burn grate holes and
reduce air flow.
Ash content of pellets tends to increase as the age of the raw material, the amount of dirt and
the amount of bark in the pellet increases.
4) BTU: Most woods are assumed to provide approximately 8,600 BTU per pound of wood. As
ash content, moisture content and the amount of time dead wood is exposed to the elements
increases, the BTUs per pound goes down.
PLEASE NOTE: THE QUALITY OF SOME FUELS IS SUCH THAT THEY ARE NOT
SATISFACTORY FOR BURNING IN PELLET STOVES. LOCAL DEALERS MUST KNOW
AND INFORM CUSTOMERS ABOUT THE QUALITY OF THEIR PELLETS!