Pressure Switches
Pressure switches are mechanical devices that change the position of a contact when the measured pressure reaches the set point, controlling a pump, compressor, fan or alarm circuit. The category includes booster set and pump switches, compressor switches with unloader, bellows pressure switches for refrigeration and boiler installations and high-pressure switches for hydraulic systems.
Pressure moves the contact mechanism through bellows or a diaphragm against an adjustable spring; on most models the gap between cut-in and cut-out is set separately. Industrial bellows types have an SPDT contact that switches 16 A at 400 V in AC-3 class, and the housing reaches IP55 with accessories.
Main Applications
- Starting booster sets and pumps when pressure drops and stopping when it rises
- Unloading compressors with unloader switches
- Low and high pressure protection in refrigeration and air conditioning circuits
- Water pressure safety in boiler and heating installations
- Pressure signal at 160–500 bar on hydraulic units
Technical Data
| Operating principle | Pressure moves the contact via bellows or diaphragm against an adjustable spring |
|---|---|
| Setting ranges | From −0.2…7.5 bar up to 40…400 bar (depending on model) |
| Dual type | Low side −0.2…7.5 bar · high side 8…32 bar |
| Contact system | SPDT (industrial bellows type) |
| Contact load AC-3 | 16 A / 400 V |
| Contact load AC-15 | 10 A / 400 V |
| Contact load DC-13 | 12 W / 220 V |
| Ambient temperature | −40…+65 °C (80 °C for up to 2 hours) |
| Medium temperature | −40…+100 °C |
| Degree of protection | IP30; IP44 / IP55 with accessory |
| Pressure connection | G1/4 A (bellows type); 1/8″–1/2″ on other types |
| Cable entry | Rubber gland for 6–14 mm cable |
Material Options
| Part | Pump / booster set type | Industrial bellows type | High-pressure (hydraulic) type |
|---|---|---|---|
| Setting range | 1–5, 1–6, 2–8, 2–11, 3–11, 3–12 bar | −0.2…7.5 bar; 8…32 bar on dual type | Up to 160 and 500 bar; 40–400 bar |
| Sensing element | Depending on model | Phosphor bronze or stainless bellows | Depending on model |
| Contact | Single-phase and three-phase types; rating depending on model | SPDT · AC-3 16 A / 400 V | Depending on model |
| Pressure connection | 1/4″–1/2″ (depending on model) | G1/4 A | 1/4″ |
| Protection | Depending on model | IP30; IP44 / IP55 with accessory | Depending on model |
Note: Contact load, temperature and protection values are from the manufacturer data sheet of the industrial bellows pressure switch family; setting ranges of pump, compressor and high-pressure switches are taken from product names and their other values vary by model. Separate gas and air pressure switches are used on gas and air lines.
Advantages
Direct control
- The contact switches the pump or compressor circuit directly.
- No separate controller is needed.
Setting and differential
- Cut-in point is set with the range and differential spindles.
- Frequent cycling is avoided.
Dual pressure monitoring
- Dual types monitor low and high pressure in one housing.
- Two separate switches are not needed in refrigeration circuits.
Wide range
- Options from −0.2 bar up to 400 bar.
- Types suitable for water, air, refrigerant and hydraulic oil.
Construction and Design Features
- Bellows or diaphragm sensing element
- Range and differential setting spindles
- SPDT or multi-pole contact system
- Cable gland and terminals
- 1/8″–1/2″ threaded pressure connection
Send us the medium, cut-in and cut-out pressures, motor type and connection size via the Request a Quote form and we will propose the right pressure switch.
How to Choose?
- Define the mediumWater, air, refrigerant or hydraulic oil determines the wetted part material.
- Choose the rangeCut-in and cut-out pressures should be inside the setting range, away from its limits.
- Check phase and currentChoose the contact design and current rating for a single-phase or three-phase motor.
- Decide on reset typeManual reset types are used for safety duties, automatic reset types for pump control.
- Look at protectionChoose a higher IP housing or protective cover outdoors and in damp areas.
Complementary Products
Why ORFA?
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Our sales team will prepare the best solution for your needs.