A leaking plate heat exchanger is a symptom, not a diagnosis. The fix depends entirely on where the leak comes from, so the first job is always to find the source.
External leaks at the plate pack
Leaks at the edge of the pack are usually gasket-related. Gaskets that have hardened, taken a permanent set or been attacked by the media no longer seal. Gasket grooves fouled with debris, or gaskets that have come unseated, have the same effect.
Incorrect compression
The pack must be compressed to its specified dimension. Too loose and gaskets can’t seal; too tight and gaskets are crushed and plates can deform. Uneven tightening across the tie bolts can cause leaks on one side of the pack only. A dimensional check on site identifies this quickly.
Internal leaks between the two media
Internal leaks — one medium getting into the other — are more serious. They are commonly caused by cracks or pinholes in the plates from corrosion, fatigue or pressure spikes. They can’t be seen from outside, which is why plates are crack-tested during a workshop service.
Leaks at the connections
Not every leak near the exchanger is in the exchanger. Flange gaskets, port liners and connecting pipework can leak too. It’s worth ruling these out before opening the pack.
How leaks are diagnosed
- Locate where the fluid appears and which medium it is
- Check the pack dimension against specification
- Inspect tie bolts and frame alignment
- Open the pack and inspect gaskets and plates if needed
- Crack test the plates if an internal leak is suspected
Don’t keep tightening
Tightening a leaking pack beyond its specified dimension may stop the drip for a while, but it crushes the gaskets and can damage the plates — turning a regasketing job into a plate replacement. See on-site servicing and cleaning and regasketing.
Have a leaking unit? Request a quote or call (02) 9897 7371.