TM 10-4520-262-12&P 0005 00
INSTALLING THE AIR SUPPLY AND RETURN DUCTS
General. Two air ducts, 8 feet in length and 10.5 inches in diameter, connect to the inlet and outlet ends
of the heater and move air from the interior of the tent through the heater and back to the interior of the
tent. Although the two ducts appear to be identical, they differ in that one is specifically designed to move
unheated air from the tent to the heater (the air supply duct) and the other is designed to move heated air
from the heater to the tent (the air return duct).
The two ducts can be differentiated from one another by observing the direction of the air flow tags and
the location of the debris grill. The air supply duct (1), which conducts cool, breathable air from the tent to
the breathable air inlet of the heater has an air flow tag with a directional arrow that points from the end of
the duct with the debris grill toward the open end of the duct. An inspection of the interior of the air return
duct shows that the end with the debris grill has a SILVER lining.
The air return duct (2), which conducts heated air from the Space Heater Convective to the tent, has an
air flow tag with a directional arrow that points from the open end of the duct toward the end of the duct
with the debris grill. An inspection of the interior of the air return duct shows that the end with the debris
grill has a GREEN lining.
If the air flow tags are damaged or missing from the duct(s), one can also tell the difference between the
two ducts by inspecting the interior. Looking in one end of a duct, it can be seen that the interior has a
silver colored lining. Reversing the duct and looking in the opposite end of the duct, one will observe that
the duct has a green colored lining. This is due to the fact that the interior of the duct is designed to
promote air flow within the duct from the silver lined end to the green lined end. If the debris grills should
ever be separated from the ducts, they can be properly assembled by placing one debris grill at the green
end of the duct and one debris grill at the silver end of the other duct.