General Questions
In general, BCS does not like being heating engineers because there are so many variables in meeting a customer's needs with wood heat. Ceiling height, desired temperature, frequency of loading, building insulation, spray booths exhaust and the location of the plant can all significantly impact the expected output of the wood furnace per square foot of building. Every BTU produced by our wood furnaces is one less expensive BTU that needs to be produced from other fuels. However, in general, we tell perspective customers wanted to rely entirely on the furnace for heat:
- 250,000 BTU furnace: Shops under 6,000 sf
- 500,000 BTU furnace: Shops 10-12,000 sf
- 800,000 BTU furnace: Shops over 12,000 sf – 25,000 sf
*These numbers are based on a space that is insulated with standard ceiling heights.
The Front and back of the furnace is hot but the sides can be touched without being burned. You would not want to leave your hand on the side of the furnace for long periods of time because they too do radiate heat but not enough heat to cause injury.
Load up the furnace with the largest pieces of wood available and damper down the under fire air. The furnace hot air distribution fan has a thermostat which will cycle the distribution of warm air into the plant to ensure the firebox and air blowing into the plant maintains a minimum temperature. The temperature of the firebox when you return in the morning will depend on the size of wood it was loaded with the night before but almost all customers report not needing a match to restart the fire in the morning. Just rake the hot coals forward and throw in more wood in the morning.
Just rake the hot coals forward and throw in more wood.
Our shop heaters do radiate heat some heat off the furnace skin but the vast majority of heat is blown from the furnace by the large fan mounted on top of the furnace.
Dry sawdust and shavings turn into a gas when thrown into the firebox by hand. This gas can and will flash back on the operator. So shoveling this fuel into the firebox is dangerous and not recommended.
but briquetting sawdust and shavings into pellets enables more of this material to be burned. Too much dust, shaving or small chips can smother the fire by preventing air from circulating through the pile of fuel. When burning large qualities of this material, grates must be added to the furnace to enable air to get under the pile of fuel. These grates create poor air flow for burning chunk wood or pellets and so are not recommended.
No, this is a hot air furnace and not a boiler.
Depends on when the order in placed. BCS tries to maintain an inventory but often has a 2-4 week lead time during our busy fall season.
The hot air Shop Heater should not be installed in a plant which has significant negative pressure. Although the system has an induced fan which will overcome a little negative pressure, significant negative pressure can literally suck the smoke down the stack and into the plant. If your plant has negative pressure we suggest using the furnace to pre-heat make up air. Attached is a diagram which shows how this installation can be accomplished.
The Shop Heater design has been in the market place for almost 30 years and has developed a remarkable safety record. Many insurance companies already insure companies who have this furnace and are familiar with this safety record. Generally, insurance companies want to ensure that the installation meets all local and state codes and will request documentation that the local fire marshal will approve the installation.
Yes, BCS sends the UL safety reports when quoting furnaces because it is likely that the local Fire Marshal will ask for it.
All furnaces are quoted F. O. B. Contoocook, NH. BCS will include shipping costs with the proposal upon request.
In addition to delivery, the system will need to have two fans wired (magnetic started are not included), some duct work for air distribution, a sheet metal roof shoe where the stack penetrates the roof, and stack erection.
The hand fired BCS Shop Heater will burn a wide range of wood from kiln dried lumber to 45% moisture content green wood. It is dangerous to hand fire fine, dry dust because it can flash back on the operator.
When extremely green wood is burned the furnace will need a “forced draft kit” ($350) to increase the air flow through the firebox. Man made woods such as particleboard, MDF and OSB burn extremely cleanly at high temperatures. Below about 800 degrees, these fuels do not burn completely and will produce odors. In States that permit burning this man made wood, BCS recommends that customers start fires with virgin wood and only add this fuel when the firebox temperature gets above 800 degrees. In addition, before leaving at night we also recommend stoking the fire with virgin wood to ensure the system does not produce odors when the fire burns down over night.
Cardboard and paper will certainly burn if you put them in a Shop Heater. Most States have special regulations governing wood burning which do not include burning paper, cardboard and other “trash”. The BCS Shop Heaters are designed to burn wood and we can not guarantee the safety, efficiency or legality of burning anything else.
BCS has experimented with systems which burn whole pallets and decided not to offer one for sale. All designs of “whole pallet burners” have inefficient combustion and so smoke. More importantly, these systems just do not last under the stress of hand firing. If you find a company offering a whole pallet burner ask them to talk to someone who has had it more than five years. BCS has many references that have had their Shop Heaters more than ten years.
Hot air systems can be used for heating kilns so long as the kiln does not require precise temperatures. Please call BCS to describe you needs.
The amount of stack required depends on where the stack is located compared to other buildings. We recommend that the stack penetrate a flat roof by at least four feet if there are no other buildings around. On a slanted roof, the stack should be as high as the peak to ensure that wind coming over the peak does not create a down draft. If another higher building is within 25’ it is a good idea to take the stack above this nearby building.
Plant location, ceiling height, desired temperature, frequency of door openings, activities in the plant, building construction and how often a furnace is loaded all effect the sizing of a wood furnace. However, for insulated buildings in northern climates with 16’ceilings, where the doors are not opened very often and the furnace is loaded as needed with a desired temperature of 60 degree, BCS recommends the 250,000 BTU furnace for building up to 6000 square feet, the 500,000 BTU/hr furnace for building up to 12,000 and the 800,000 BTU/hr furnace for larger buildings. Most of our larger systems are used as base load heaters because every BTU from the furnace is one less BTU your need from fossil fuel.
Still have questions? Please call us at 508-798-5970 or email us at info@biomasscombustion.com.
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