Category
Differential Pressure Switches
Beck 908 and 930 differential pressure switches for filters, fans and ducts, including UL-approved models.
A differential pressure switch trips a contact when the pressure difference between two points crosses a set value, alarming a blocked filter, a stalled fan or a dry-running pump. The Beck 930 Climair® covers air from 20 to 5000 Pa, the Beck 908 covers liquids from 40 to 1000 mbar, and a UL-approved 930.8x version is available.
8 Products · Differential Pressure Switches
ATEX Differential Pressure Switch 930 Ex Adjustable
adjustable from 20 to 5000 Pascal for Ex zones 1, 2 and 21, 22 with ATEX type examination
Differential Pressure Switch 908 Adjustable
adjustable from 40 to 1000 mbar
Differential Pressure Switch 911.82 Factory-Set
factory-set from 20 to 1000 Pascal
Differential Pressure Switch 930 Adjustable
adjustable from 20 to 5000 Pascal
Differential Pressure Switch PS
Differential Pressure Switch Series: 908
Differential Pressure Switch Series: 930
Differential pressure switches 930.8x Climair® with UL approval
Selection guide
Differential Pressure Switches Guide
How a differential pressure switch works
The switch senses the pressure difference between two ports on a diaphragm held by a spring. When the difference crosses the set point, the diaphragm moves far enough to trip the contact; when it falls back, the contact resets. No power supply is needed, which makes the switch a simple, low-cost way to prove a fan is running, alarm a dirty filter or catch a blocked strainer.
How to choose a differential pressure switch
- Medium: choose the Beck 930 Climair® for air and other non-combustible, non-aggressive gases, or the Beck 908 for liquids and gases, including aggressive media when specified.
- Range: the 930 covers 20 to 5000 Pa in overlapping ranges; the 908 covers 40 to 200 mbar or 150 to 1000 mbar.
- Setting: the 930's scaled knob sets the switching point without a manometer; the 908 is set with an adjusting screw.
- Protection: IP54 or IP65 on the 930, depending on the version.
- Materials: the 908's diaphragm is available in EPDM, NBR, FKM or silicone, for a maximum operating pressure of 10 bar.
- Approval: the 930.8x Climair® adds UL approval for projects that require it.
For a continuous signal on air handling applications, see air differential pressure transmitters. For liquid circuits, see liquid differential pressure transmitters.
FAQ
Common questions
How do I set the switching point on a differential pressure switch?
On the Beck 930, turn the scaled knob to the pressure you need; no manometer is required. The Beck 908 is set with an adjusting screw instead. Both trip a contact when the differential pressure crosses that point and reset once it falls back.
Can a differential pressure switch handle liquids as well as air?
Yes, with the right model. The Beck 930 Climair® is built for air and non-aggressive gases up to 5000 Pa. The Beck 908 is built for liquids and gases, including aggressive media when specified, up to 10 bar operating pressure, with a choice of diaphragm materials.
What is the difference between the Beck 930 and the UL-approved 930.8x?
They share the same Climair® design and pascal ranges for air and gas. The 930.8x Climair® additionally carries UL approval, for projects, panels or export machines that specifically require UL-listed components.
What diaphragm material should I choose for the Beck 908?
It depends on the liquid or gas. EPDM, NBR, FKM and silicone diaphragms are available, covering water, oils and a range of aggressive media. Tell us the medium and operating temperature, -10 to +80 °C, and we'll confirm the right combination.
Is a differential pressure switch enough, or do I need a transmitter?
A switch is enough when you only need an alarm or interlock at one set point, such as a dirty-filter warning. If you need to see or trend the actual pressure drop over time, choose a differential pressure transmitter instead.
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