Hotblast Wood Furnace Problem

Cold Furnace

• An incorrectly set Hotblast furnace control is a common cause for a lack of heat and it can be easily remedied by setting the temperature higher. If resetting the thermostat does nothing, another possible cause is improperly seasoned wood that is burning too quickly and not producing high heat. An improper flue draft is another possible cause of low heat in Hotblast wood furnaces, so it is important to attach the flue flush with the emissions pipe so the fire receives adequate oxygen to burn.

Smoke Emission

• Hotblast furnaces normally emit a small amount of smoke through the feed hatch after the first lighting since the interior coating of the unit is burning off. However, if the unit emits smoke from the feed hatch after that, it is a sign that the furnace has an insufficient upward draft, a clog in the chimney or a strong down draft. Inspecting the chimney for clogs or realigning it to produce a strong, constant upward stream of air will correct the problem.

Diminished Blower Function

• If the fire is burning normally yet the Hotblast furnace is still not heating your home, it is likely experiencing diminished blower function. Ensure the air registers and the ductwork are properly installed to eliminate those as possible causes for the malfunction. If the registers and ducts are in proper working order, then the cause for diminished blower function is likely an issue with the wiring, a bad relay or a bad motor. While it is possible to tackle such issues yourself, it is best to call in a certified technician to deal with electrical issues to preserve the warranty on the unit.

Excessive Flames

• Active flames occur from time to time within all furnaces, although the vast majority of the heat emissions are drawn from low-burning embers. Excessive flames or a violent flare-up when the feed door is opened indicates a problem. In most instances, flame spillage from a Hotblast furnace is the result of an insufficient draft that pulls the fire down through the open door of the unit rather than up toward the flue. Turning up the thermostat will increase the upward pull on the fire, which will keep it from flaring when the door is opened. Also, flames sometime flare when too much fuel is added at once, so it is best to add wood at a slow, steady pace to allow for even combustion.

Creosote Build-Up

• Creosote formation is inevitable when burning wood in an enclosed space, but a Hotblast furnace should not acquire a large amount of creosote inside the flue if it is being used properly. Using green wood inside the unit increases the amount of creosote buildup since it does not burn as cleanly as properly dried and seasoned wood. Also, adjusting the thermostat higher or lower according to the type of wood being used will lessen creosote formation. If creosote does form, it must be removed from the chimney to avoid causing a clog, which will inhibit the furnace's function and potentially cause a fire.