628 Differential Pressure Decay Leak Tester

Differential pressure decay leak tester offering uncompromising precision and accuracy.

Designed to provide clear and non-subjective results, the Uson 628 is a differential pressure decay leak tester that rivals the performance of more complex and expensive instruments. By offering five different pressure ranges, ranging from vacuum up to an impressive 15 bar, it covers a wide range of applications, from medical check valves to automotive radiators and beyond. With its highly sensitive and budget-friendly design, this tester is your ultimate ally in reducing product deviations and recall issues through the early identification of leaks.

But that's not all - the Uson 628 is packed with features that truly set it apart from the competition. With the ability to create and save up to 30 test programs, you can easily recall your preferred settings for fast and efficient testing. The electronic regulator option goes even further, allowing you to test at multiple pressures with the pre-fill option as standard.

The 628 tester is capable of running multiple tests, including differential pressure and vacuum decay, ensuring comprehensive and accurate results every time. Equipped with a 24-bit high resolution for precise measurements, as well as industry-proven proprietary sensors and valves, this tester provides reliable operation that you can trust.

Sensor Types

  • Differential Pressure


  • Max Channels-Design (1)
  • Synchronous
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Easy to use

Uson’s 628 differential pressure decay leak tester is a compact, reliable, and accurate instrument that is ideal as a budget-friendly benchtop option for a wide range of industries. The 628 leak tester incorporates an intelligently designed multi-language user interface, with the capability to collect and transmit a vast amount of data, for offline trend analysis and a deep level of insight.

The 628 is a highly flexible leak tester, offering users the ability to choose from five pressure ranges – from vacuum up to 225 psi (15 bar) to cover a wide range of applications, making it useful for a wide range of industries and applications. Internal memory allows users to create and save up to 30 test programs, for fast recall of test parameters.

The 628 easily accommodates multiple test pressures

For applications that need to test multiple test pressures, the 628 offers an optional electronic regulator. With the electronic regulator option, the 628 can be programmed to test a part at different test pressures in a sequence. Additionally, the test programs can be linked, serving to further the automation of the test sequence. Another benefit with the electronic regulator is that it adds an increased level of security. It is only accessible through the programming interface and can be locked and safeguarded to prevent unintended changes. This is a significant advantage over a manual regulator, which can be adjusted from the back of the instrument.

The 628 leak tester is easy to use and requires minimal operator training

The 628 leak tester was designed to be easy to use in a busy environment. A backlit user interface makes accessing information easy, while bright uniquely designed lights on the front panel allow for at-a-glance monitoring from across a room. The menu system is intuitively structured to make setup and operation practically effortless.

Reliable performance, with accurate results every time

The 628 leak tester is a surprisingly powerful instrument, packaged in a simple design. Incorporating the differential pressure decay method to provide highly accurate and reliable results, the 628 can run test cycles to display leak rates in a range of pressure units or volumetric units using the leak rate calibration option. The 628 incorporates Uson’s industry-proven proprietary sensor and valves, to deliver the type of results that are expected from more sophisticated instruments.

Access to an extensive amount of information to help you manage your process

The 628 leak tester ensures a high level of control over the instrument. With a convenient USB port, firmware updates, data transfers, and program backups are easy. Program security and data access are controlled by a password, while couple safety valves control the position of the machine in the event of a power failure.

Navigating the Uson 628 is a breeze thanks to its backlit user interface. Accessing specific information and viewing results has never been easier. And with its intelligently designed menu system, setup is quick and hassle-free, even for new users. Plus, for your convenience, the Uson 628 offers factory-programmed language options, including Chinese and Spanish.

Designed to meet the highest standards of quality and performance

With a durable, splash-proof and dust-proof enclosure, the 628 leak tester is designed for quality in manufacturing laboratory environments. It features a reliable, solid-state hard drive for high-speed data transfer, and accommodates single-range 0-20 mbar calibration for accurate results. Plus, the 628 features an advanced, upgrade friendly design that makes service and maintenance easy.

Flow Range: 20 mbar/2000Pa/0.29 psi
Pressure Range: -950 mbar/-95 kPa/-14 psig
1 bar/100 kPa/15 psig
4 bar/400 kPa/60 psig
10 bar/1000 kPa/150 psig
15 bar/1500 kPa/225 psig
Communications: RS-232 ports / tester 1
Host USB 2.0 ports 1

Inputs/Outputs: Max Decision Sensors / tester 1
Max Sensors / channel 1
A/D resolution (bits) 24
Maximum discrete digital outputs/channel 7
Discrete digital outputs / channel 8
Digital I/O Voltage Level 24vdc
Physical Characteristics: Size (H*W*D) Inches 5.3" X 12.6" X 13.2"
Weight lbs 22lbs
Color Display size 4.3"
Front-panel membrane buttons 7
Integrated pneumatics
Test Ports 1
Calibration Ports 1
Pendant Style Remote Control

Data: Accept/ Reject / Total Counts N/A
Min/Max Test Result N/A
Average Pass/Reject Result N/A
Standard Deviation of all test results N/A
Range of test results N/A
Pressure versus time plot N/A
User Interface:

Real time clock

Program select via Digital Inputs

Start / Abort via Digital inputs

Software: Accept/ Reject Step Markers - Pulsed Embedded Unix Based
Password protection
Addressable Programs 30
Internal Test Result storage (test cycles) 500
Sensor Calibration Software zero & span.
Product Brochure
Download User Manual
User Manual (Spanish)
628 Data Sheet
Troubleshooting Guide