1. A heat exchange assembly for exchanging heat between a coolant and a gaseous medium, comprising:an outer jacket;
a plurality of gas tubes positioned within the outer jacket; and
a self-cleaning system positioned about the plurality of gas tubes,
the self-cleaning system comprising:
a plurality of chains attached to an upper bar to extend from the upper bar through the plurality of gas tubes,
an agitation device comprising an air cylinder and a piston, the piston extending from the air cylinder to contact the upper bar for reciprocal movement of the upper bar and attached plurality of chains, and
the upper bar connected to a channel bar by a support wire.