Thermostatic Air Cleaner: Description and Operation

Fig. 5 Typical heated air intake system:

Intake air temperature is controlled by the heated air intake system, Fig. 5. This system consists of a mixing valve containing a damper door (4) and a wax pellet thermostatic switch (5). The mixing unit receives hot air from a heat shroud surrounding the exhaust manifold and cold air from a second duct. When incoming air reaches a temperature of 59-68°F (15-20°C), the wax pellet switch expands and closes off hot air entry thus admitting cold air. The damper is fully opened to cold air at 78.8°F (26°C).