Profile: The Henry G. Dietz Co. Inc. engineers and designs products with low pressure/vacuum technology. We also specialize in manufacturing high quality products for unusually harsh environments. We offer free software as well as engineering booklets to aid in the proper application of our products. Our products are used for detecting air flow, dirty air filters, pressure/vacuum, and to measure & monitor these functions in clean rooms. Our vane type airflow switch is the simplest device that can detect airflow. If the cubic feet per minute output of the blower are known, the air velocity can be found by dividing the cubic feet per minute by the area of the duct in square feet. The vane of the model 103B switch is marked with lines outlining the area of the vane used to detect air flow of 500 to 2,500 feet per minute. Our model 502 dirty air filter indicator alerts maintenance personnel when a filter must be replaced. It requires a 1/4" diameter hole to be drilled in a vertical wall to obtain a reference pressure outside the ventilated area. The model 602 is suitable for monitoring the pressurization of clean rooms and ventilated areas. It detects dirty air filters and failure of blower motors.