Siemens QBM81 is a differential pressure switch specifically designed for monitoring under an overpressure in ventilation as well as air conditioning plants. This tool has a pressure of 20 to 5000 Pa, single-pole changeover output, an IP54 protection class, and a temperature range of 0 to 70 °C.  

Features:

•  Monitors air filters, airflow, and fan belts
•  Can be used to monitor the pressure in clean rooms, kitchens, etc.
•   Easy to mount  

Application:

The QBM81-... Differential Pressure Switches are used to monitor differential pressure, under pressure, and overpressure in HVAC installations. By measuring differential pressure, they monitor the state of air filters, prevailing airflows, damaged fan belts, and overpressure in cleanrooms, kitchens, etc. They are also used to monitor differential pressure and positive and negative relative pressure in HVAC systems.