The function of component parts of a typical truck evaporator are defined. These include evaporator coil, expansion valve, temperature control, blower, and air distribution system. The various heat inputs to the truck cab depend on engine cover temperature, type of insulation, air infiltration at various road speeds, number of cab occupants, etc. Outside air temperature is the greatest contributor to the heat which must be absorbed by the evaporator.
In designing evaporators, space available in the cab must be considered so that the location of air discharge is most beneficial to occupants.
The repair mechanic should be sufficiently trained to have a better understanding of the fundamentals of the system. With proper instructions to the truck operator and a scheduled preventive maintenance program, field repair problems should be alleviated.