On occasion, a plate heat exchanger (PHE) can fail when a plate develops a small crack or in some rare instances when a gasket is dislodged or damaged. When one of these failures causes the two fluids to mix, it’s called a differential leak. This can be particularly damaging in the food, beverage and chemical industries, and can lead to significant downtime. Fortunately, plate heat exchangers are modular, and once the defective plate or gasket is located, it and an adjacent plate simply need to be removed and the PHE can go back into service, operating at a slightly decreased capacity until you acquire the replacements. So how do you find the defective plate? We’ve outlined four simple steps below.  

Step 1: Drain, Isolate and Dry

The first step is to drain the plate heat exchanger and isolate it from your system. The actual test relies on water, so you’ll have to wait for all the plates to dry. You can disassemble it now to speed up the process, but you’ll have to reassemble it for the next step, and then disassemble it again for the step after that.

Step 2: Water Test

Secondly, run water through one side of the plate heat exchanger only. Each plate will subsequently have a wet side and a dry side, but the leaky plate and the adjacent plate will be wet on both sides, making them easy to identify by touch.

Step 3: Disassemble

Thirdly, disassemble the plate heat exchanger according to the manufacturer’s guidelines. For this step, it’s best to leave the plates in the frame so you can go through them one by one more easily.

Step 4: Examine

Last, look at each plate individually and note any that are wet on both sides. Once you’ve removed all the plates that are wet on both sides, you can reassemble the PHE and put it back in service at reduced capacity until you have the appropriate replacement parts. 

More Resources

If you’re reading this article because your plate heat exchanger has failed, you may find these articles helpful:

• How to Troubleshoot a Plate Heat Exchanger
• Good Maintenance Habits for Plate Heat Exchangers
• How to Disassemble a Plate Heat Exchanger

If you’re not sure what type of heat exchanger is the right product for you, take a look at our Overview of Plate Heat Exchanger Technology.

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