Understanding hopper-fed coal stoves (Gravity type)
Many European and some American coal stoves use a hopper to hold coal that is to be fed onto the fire. Some popular brands that use this design are: Surdiac Efel Franco-Belge Certain Vermont Castings Vigilant Models
Surdiac Stove w/Hopper
Although many of the same tips mentioned in our coaltips article apply, it is also important to have an understanding of the way these products work.
The drawing on the left shows an inside view of a typical hopper-fed coal stove. Coal is loaded into the top of the stove and, once the stove is going well, should be kept full or nearly full. Because of the air flow design only the coal in the lower part of the firebox will burn.When this coal burns completely and turns to ash, new coal will take its place, helped along by your raking/shaking of the grates.
(efel type shown in cutaway. Surdiac and Vermont Castings use a center-fed hopper - operation is similar)
The temperature of these stoves is usually controlled by a thermostat with either a bulb-type or bimetallic element. European Coal Stoves often use a thermobulb connected to a control knob. The dial opens the draft inlet (higher number is more open)- and then when the stove gets hot- the thermobulb closes and opens the inlet to even out the effect of the fire. The bimetal thermostats function in much the same fashion, but not as accurately.
Fuel and Hopper settings - Most of these stoves are designed to use pea (smaller) coal, which tends to flow onto the grates easier. Inspect your stove for different hopper adjustments and experiment (middle setting is best on most).An exception is the Vermont Castings Vigilant, which uses nut sized. European coal stoves work best with a low-ash coal. Poor fuels will result in shorter burn times and less heat output. Old Company Lehigh brand anthracite coal is known for low ash content.
Chimney and Draft issues - Hopper-fed coal stoves require a better draft than most woodstoves. However, if you have too strong of a draft, this can lead to overfiring of the stove and short burn times. The solution is to use a barometric draft regulator (flapper) on the stove pipe of these coal stove. Precision coal stoves also do not take well to being operated in temperate weather. Wait until the temperature falls below 45 degrees (24 hours/day) to use your coal stove.
Many of these stoves contain heat exchangers on the side and rear of the unit which funnel the exhaust gases and trap fly ash from the fire. These passages need regular cleaning as the ash buildup can reduce the drat and heat output of the stoves.
Starting - Since these stoves have such a small grate area, they are more difficult to start than “batch-fed” coal stoves. Use either very small pieces of oak or good hardwood or matchlight charcoal (preferred method). Our coaltips will tell you the rest.
Parts: Check with Woodman Associates at https://www.hearth.com/partsplace.html for Surdiac and other hopper-fed coal stove parts.