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Vacuum Pressure Switch YL-802
A digital switch built for the negative side of zero. It reads vacuum down to -120 kPa on a display, lets you set the alarm point anywhere in that band, and drives a relay when the vacuum crosses it. A dedicated vacuum tool, not a gauge switch run backwards.
- Range: 0 to -120 kPa
- Alarm point: settable -3 to -120 kPa
- Display resolution: 0.1 kPa
- Output: relay, 220 V / 24 V 5 A
- Supply: 24 VDC or 220 VAC
- Connection: M20 x 1.5
Vacuum control has its own problem: the working span is small, just 0 to -100 kPa of usable depth, so a switch needs fine resolution to set a useful point. The YL-802 is built for it. It reads the vacuum to 0.1 kPa on the display, takes a settable alarm point anywhere from -3 to -120 kPa, and trips a relay when the vacuum reaches it. Because it samples five times a second, it catches a vacuum drop quickly enough to protect a pump or a held part.
Overview
The YL-802 is a digital vacuum pressure switch covering 0 to -120 kPa. Control resolution is 1 kPa and the display resolves 0.1 kPa, so you both set and read with precision. It runs on either 24 VDC or 220 VAC, which makes it easy to drop into machine or panel wiring, and its relay carries 5 A. It works with media that do not corrode stainless steel. Where you need positive-pressure switching instead of vacuum, see the electronic YX-18 or the mechanical models in our pressure switch range.
Working principle
A pressure sensor reads the vacuum and a processor converts it to the value on the display, sampling five times a second. The processor compares the reading against the alarm point you set; when the vacuum reaches that depth, it energizes the relay to drive a pump, valve, or alarm. As the vacuum eases back past the reset level, the relay drops out. Doing this digitally is what lets the YL-802 hold a fine, repeatable alarm point across a narrow vacuum band that a mechanical switch would struggle to resolve.
Technical specifications
Representative specifications; confirm the exact build per datasheet.
| Parameter | Specification |
|---|---|
| Measuring range | 0 to -120 kPa |
| Alarm point | Settable, -3 to -120 kPa |
| Control resolution | 1 kPa |
| Display resolution | 0.1 kPa |
| Output | Relay; load 220 V / 24 V 5 A |
| Sampling rate | 5 times per second |
| Supply voltage | 24 VDC or 220 VAC |
| Working temperature | -20 to +65 °C |
| Process connection | M20 x 1.5 |
| Wetted compatibility | Media that do not corrode stainless steel |
Setting the alarm
The alarm point is settable anywhere from -3 to -120 kPa, and you enter it directly against the digital reading, so there is no calibrating against a separate gauge. Two things help in vacuum work. First, set the point with margin from full vacuum: holding right at -100 kPa leaves no headroom, so set the alarm a little shallower so the system has somewhere to recover to. Second, use the fast sampling to your advantage on leak detection; because the YL-802 updates five times a second, it flags a sudden loss of vacuum quickly, which protects a held part or a running pump. Where you need a continuous analog signal as well, pair it with one of our pressure transmitters ordered for a vacuum range.
Applications
The YL-802 suits negative-pressure control and protection:
- Vacuum pumps, with low-vacuum alarm and protection
- Vacuum chucks and pick-and-place holding
- Vacuum packaging and forming lines
- Degassing, drying, and filtration under vacuum
FAQ
What is a vacuum pressure switch?
A vacuum pressure switch monitors negative pressure, pressure below atmospheric, and changes an electrical contact when the vacuum reaches a set level. It is used to confirm a pump has pulled vacuum, to protect a process if vacuum is lost, or to control suction in handling and packaging. The YL-802 is a digital version that reads from zero down to about -120 kPa and switches a relay at the level you program.
How to test a vacuum pressure switch?
Connect the switch to a controllable vacuum source and a reference gauge, then draw the vacuum down through the set point while watching the contact with a meter. The relay should change state right at the programmed value and reset at the deadband below it. On a digital unit like the YL-802 you can also read the live value on the display and compare it with the reference gauge, confirming both the reading and the switching are accurate.
How to adjust a vacuum pressure switch?
On the YL-802 you set the trip level digitally: enter the set point and the reset point through the buttons rather than turning a spring screw. Choose the vacuum level at which the relay should act and how far it should recover before resetting, so it does not chatter near the threshold. After setting, cycle the vacuum a few times and watch the display to confirm it switches cleanly and repeatably at your values.
Request a quote
Tell us four things and we set the unit for your vacuum:
- Alarm depth you want, within -3 to -120 kPa
- Medium and whether it is compatible with stainless steel
- Supply (24 VDC or 220 VAC) and the relay load
- Process connection (M20 x 1.5 or adapter)
Ordering example: YL-802, alarm at -80 kPa, 24 VDC supply, relay to a backup pump, M20 x 1.5.
Tell us the application and we configure one unit, not a shelf part. Have a vacuum point we have not covered? Reach our application engineers.