Air Cleaner - Thermostatic: Operation

When incoming air temperature, as sensed by bimetal sensor, is below about 86°F (30°C), air bleed valve of bimetal sensor is closed. This allows intake manifold vacuum to be applied at vacuum motor diaphragm, which opens the air control valve. This is the hot air only position.

When incoming air temperature is above about 113°F (45°C), air bleed valve of bimetal sensor is fully open. With air bleed fully open, vacuum is no longer able to operate vacuum motor diaphragm and control valve is closed (regardless of intake manifold vacuum pressure). With control valve closed, only cold air is admitted to air cleaner.

At temperatures between closed and opened positions, control valve will be positioned to blend both hot and cold air to moderate temperatures reaching air cleaner. Through this method, air temperature of incoming air is kept nearly constant.