Heat Exchanger Integrity Testing

Unison specialise in non-destructive Heat Exchanger integrity and holding time testing of all makes and models of Heat Exchangers.  Our Heat Exchanger Integrity Testing systems (HEIST and Pastest+) are the most advanced methods on the market for locating defects in a Heat Exchanger without having to open it up on site.

Leading the field with our unique, patented Heat Exchanger Testing technologies, Unison is revolutionising the way the food, liquid processing and pharmaceutical industries test their pasteurisers and plate heat exchangers by providing innovative, cost effective solutions to their everyday problems. Instead of having to rely on outdated methods of Integrity and holding tube testing, Unison empowers companies to take control of their own testing, allowing testing to be done quickly and effectively leading to reduced downtime and savings on cost.

Having tested thousands of Plate Heat Exchangers over their 80 years experience in the industry, Unison weren’t happy with the systems that were available and knew that we could develop unique solutions that would make daily self testing of Heat Exchangers possible. 

Testing on your equipment should be thorough, quick, and professional. Our expert testing services are outlined below. 

Maintenance support contracts are also available with 24/7 cover, 365 days per year.




Pastest+ has been validated by Campden BRI, the UK’s leading independent food and drink research organisation. 

“The test was noted to be rapid,” stated researchers. “The technology was considered to be very effective for simplistic systematic testing the integrity of plate heat exchangers.” 

Solve your Quality Control Challenges with Pastest+ 

Every plate heat exchanger is vulnerable to failure during its lifespan. This can result in cracks and holes in pasteurisers and critical heat exchangers. 

These defects may lead to contamination - yet they are difficult to diagnose without dismantling the equipment. This time-consuming process can lead to production loss and unwarranted downtime. 

This is where Unison come in. Our minimum-disruption Pastest+ is transforming process equipment testing worldwide, resulting in substantial cost and time savings. Rapid and accurate, the research-backed system significantly reduces production downtime.

Introducing Pastest+ 

Unison’s Pastest+ is a non-destructive leak detection testing service for pasteurisers and plate heat exchangers. Non-destructive, reliable and fast, the system takes just 1 to 15 minutes depending on the size of the equipment.

A patented testing method that can rapidly detect small leaks in plate heat exchangers (without the need to open the plate pack), the PasTest+ system is designed to confirm the integrity of consumers’ plate heat exchangers - reducing the chances of a product recall. The system can accurately test several heat exchangers in one day, putting an end to costly production downtime.

Why Pastest+? The system uses only the process water supply, which is pumped through one side of the plate heat exchanger at a measured temperature. No saline, compressed air or chemicals are introduced into the plate heat exchanger during the test. 

And that isn’t the only benefit of this state-of-the-art solution. The Pastest+ app allows users to accurately measure any change in pressure within the closed low-pressure side. With the press of a button, users can quickly monitor for an increase in pressure that would indicate a potential plate defect.

Look no further than Pastest+ for rapid, accurate results and unprecedented peace of mind. The system provides all the necessary documentation to ensure your heat exchanger plates are free from defects.

Why use Pastest+ 

  1. Non-destructive PHE testing technology - no dismantling of plates, with minimum production disruption. 
  2. Features an integrated, fully-automatic holding time test facility.
  3. Only uses process water to detect cracks as small as 30 microns. No saline, compressed air, gases or chemicals are introduced into the plate heat exchanger during testing.
  4. Takes just a few minutes. 
  5. Immediate results, which greatly reduces downtime. 
  6. Test certificates generated automatically by the Pastest+ system.
  7. Campden BRI-validated.
  8. Operator-friendly: compact in design and simple to use. 
  9. Results generated via QR code in the newly-launched Pastest+ app.
  10. Comprehensive test and service history of each user’s PHEs stored directly in the Pastest+ app.

Pastest+: A Seamless Testing Process

Pastest+ technology detects pressure increases in a closed volume of the plate heat exchanger. It is capable of detecting small leaks to an accuracy of 30µs.

Unison’s service engineers will run a test on your plate heat exchanger using the Pastest+ app and system. Without dismantling any plates - and only using process water - the system will identify potential leaks faster than ever. 

Following the test, a QR code will be generated and the test results printed (and applied to the applicable heat exchanger). Using the QR code, you can view your test result details. These results are automatically-generated during testing and cannot be manipulated by operators. 

The Pastest+ app automatically stores all of the tests results, providing personalised access to your equipment test data. A complete service history of all the customer’s PHEs will be available as well.

A Superior Testing Solution 

  • Worldwide patented technology 
  • Performs both integrity and holding time tests
  • Designed specifically for heat exchangers
  • More advanced technology than any other system (many of which are outdated and, in some cases, unreliable)
      • Easier to use
      • No risk of introducing outside contaminants 
      • Only uses the customer's process water
      • App-based recording of all data with zero risk of operator manipulation
  • Cost-effective and time-efficient

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