and to the worksite respectively located within the casing 14 are a blower 20 a fuel tank 22 and an indirect fired heater i e burner 24 the blower 20 is a centrifugal blower powered by a motor 26 the blower 20 has an axial inlet 28 connecting the air supply inlet 16 to a radial outlet 30 a generator 32 is mounted on the trailer 12 in front of the heater assembly 10 for powering electrically powered components of the heater assembly 10 including the inline heater 34 discussed below alternatively electric power could be supplied to those components via a cable coupled to a main electrical source located at the worksite it is also conceivable that the electrical components of the heater assembly 10 could be powered by an onboard battery or bank of batteries but rapid power drains at low temperatures render batteries a less preferred option particularly in cold climates referring particularly to fig2 the heater assembly 10 includes a burner 24 a fuel supply assembly 36 that supplies fuel to and from the burner 24 a combustion chamber 31 and a heat exchanger 33 the burner 24 comprises an atomizing burner having an internal gear pump not shown and one or more nozzles also not shown that open into the combustion chamber 31 the burner 24 heats air in the combustion chamber that indirectly heats air flowing through the heat exchanger 33 from the outlet 30 of the blower 20 to the air supply outlet.