ACV Galvanic Corrosion / External Corrosion

Corrosion or rust staining around connections on stainless steel ACV tank

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Mixed metals without dielectric unions, Persistent external leaks wetting insulation, Aggressive water chemistry attacking fittings

How to Fix / Troubleshooting

Safety: Isolate water and power before working on corroded fittings.

  • 1. Identify source: Determine if corrosion is from external leaks or from chemical attack.
  • 2. Repair leaks: Replace or reseal any leaking fittings, unions, or valves on the ACV tank.
  • 3. Use dielectric unions: Where copper or steel connects to stainless steel, install dielectric unions to reduce galvanic corrosion.
  • 4. Replace heavily corroded parts: Swap out any fittings that have lost structural integrity.

If the tank shell itself is corroded through, replacement of the tank is required.

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Repair Difficulty

Medium 3/5

Required Part

Tank Fittings / Dielectric Unions
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