Solo Plus Instructions 1-800-782-9927 Version 12-13
Tarm Biomass · 4 Britton Lane · Lyme, NH 03768
4.9 Combustion Process
Solo Plus boilers have excellent combustion efficiency.
When the boiler gets up to temperature, the draft fan shuts down and stops the supply of combustion
air to the firebox. The fire shuts down due to the lack of oxygen and does not continue smoldering to
cause smoke, creosote or overheating. When the boiler temperature drops, the fan will turn on re-
igniting the coals which have been resting on the refractory. During the off cycle, the coals stay hot
enough to burn but they will be dormant because of the lack of oxygen. The combustion process of
the Solo Plus allows to burn wood as efficiently, as clean and as controlled as many fossil fuel heating
systems.
4.10 Heat Output
The Solo Plus boiler is designed to operate in an output range from as low as 17,000 BTU’s (5 kW’s)
per hour. At maximum output, the fan will operate continuously. At lower outputs, the fan and the
fire will cycle on and off just as an oil or gas burner does to meet the heating demand. However, try-
ing to operate the Solo Plus boilers during periods of lower heat demand can be problematic due to
lower chimney draft.
4.11 Burn Time
Burn time is dependent of the type of fuel, the heat load on the boiler as well as how full the firebox is
loaded. However, the recommended maximum burn time is approximately
8 hours
. Remember to
only load the boiler with the amount of fuel that will be fully consumed in approximately
8 hours
.
Boiler Operation, Maintenance, and Service > Combustion Process
Page 41
NOTE
The chimney draft must always be strong enough to prevent reversed flow in the boiler’s pri-
mary and secondary air supply ducts. Otherwise, smoke may be forced backwards through the
boiler and emitted out of the fan when it is off. This reversed flow will maintain a smoldering
fire in the boiler and can lead to partial or complete blockage of the air supply ducts, causing
inefficient and problematic operation. It may also result on an objectionable smell of creosote or
smoke in your home. These problems are eliminated entirely when operating the boiler with
higher demand on it, such as a thermal storage tank system, and have a chimney which main-
tains proper draft.