siemens Differential Pressure Switch
siemens Differential Pressure Switch

Siemens QBM81 Series Differential Pressure Switch

Siemens QBM81 is a differential pressure switch specifically designed for monitoring under and over pressure 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.


In ventilation and air conditioning plants to:

Monitor differential pressure, underpressure and overpressure, Monitor air filters and air flows, Recognize torn fan belts and Differential pressure switches can be used in clean rooms, kitchens etc.

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Siemens Differential Pressure Switch QBM81 series is mainly used for air and nonaggressive gases which is easy to mount also features >1 mio switching cycles, highly precise setting and long-term stability.

50 Items

Data sheet

Type of switch
Single-pole change-over, multi-layer contact
Electrical Connection
3 screw terminals
Sheet-steel (galvanized)
Operating Conditions
–30 to + 85 °C ; –40 to + 85 °C
EN 61326-x Electrical equipment involved in measurement, control,and laboratory use; EMV requirements; general requirements
Cable Entry
PG11 cable gland
Fiber-glass reinforced polycarbonate
Protection class
III according to EN 60730-1
Provided alongwith and valid for 1 year, traceable to National Standards
0.25 kg
1 Year manufacturers warranty