TM 10-4520-261-12&P
SPACE HEATER ARCTIC (SHA)
0003 00
THEORY OF OPERATION
0003 00-1
THEORY OF OPERATION
General. The Space Heater Arctic (SHA) can operate using either liquid or solid fuel. In liquid fuel mode,
the heater requires an external supply of gravity-fed fuel. In solid fuel mode, the heater operates
independently of outside equipment on a regularly maintained supply of wood or coal. When using liquid
or solid fuel, combustion gases are exhausted out the roof of the shelter through the stack assembly.
The heater has variable heat output, and can be controlled by the operator. During liquid fuel operation,
heat output is controlled with the fuel flow control valve. When operating with solid fuel, the heat output is
controlled using the draft gate and by controlling the supply of fuel.
During normal operation, and with proper burn rate control, the heater will produce an even, yellow-colored
flame. The SHA will not emit smoke or other combustion gases into the space being heated. Proper
safety precautions should be maintained in the area surrounding the heater as the entire unit will be hot
during operation.
The SHA requires minimal maintenance which includes the removal of ash deposits during and after
operation in solid fuel mode as well as the periodic wipe out of the burner shell. Refer to the Preventive
Maintenance Checks and Services as detailed in work package 0010 for more information.
LIQUID FUEL OPERATION
CAUTION!
All components in the storage enclosure must be removed during
operation. Components remaining inside the storage compartment could
be damaged by high heat.
Gravity-fed liquid fuel (refer to work package 0001 for a list of authorized fuels) flows from the inverted fuel
can (1) through fuel hoses to the fuel flow control valve (2). Fuel settings are made on the fuel flow
control valve (2) based on the temperature of the fuel being used. Fuel is directed through internal orifices
and then flows into the burner up-tube (3) inside the burner shell assembly (4).
With access through the lid opening (5), a small amount of fuel is poured and ignited in the bottom of the
burner shell assembly (4). A burning piece of fuel-dampened tissue is placed at the bottom of the burner
shell assembly (4) with the help of the reamer tool (6). After five to ten minutes, enough heat is produced
by the burning priming fuel to vaporize fuel within the up-tube (3). Fuel vapors are generated and are
discharged into the downtube (7), where it enters the burner shell assembly (4), mixes with air, and is
combusted. By the time all the priming fuel is consumed, the combustion process has been established
and will continue as long as there is fuel in the fuel can (1) or the Fuel Flow ON/OFF control of the Fuel
Flow Control Valve (2) is in the ON postion.
Air, required for combustion, is drawn through the bottom of the heater and into the burner shell assembly
(4). The burner cover (8) is set into the door frame (only in liquid fuel mode), and the door (9) shut and
latched. This prevents air leakage into the upper heater body while the heater is in use which would
impair operating efficiency.
