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Electrolysis in copper pipes and pipe hangers.

Our town has installed a new Geothermal heating system. The contractor has black iron fittings connected to copper pipe and iron pipe hangers (rusting after one year). Will there be a problem with electrolysis corrosion?

Gerald M.
taxpaying citizen - Town of Sherman, Wisconsin, USA
February 7, 2010

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If the copper and iron pipes are in direct contact with each other, with a conducting electrolyte in contact with both metals, there is a good chance of a galvanic couple being set up and corrosion starting. If the copper and iron are separated by a piece plastic pipe and are not in direct contact, there should be no corrosion. The chemistry of the water will also influence the corrosion rates.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
February 9, 2010

The copper piping is filled with an antifreeze. There is no plastic between the copper pipe and black iron fittings. The iron hangers attached to copper are exposed, copper is insulated. Condensation forming on hangers will cause electrolysis?

Gerald M.
- Springstead, Wisconsin
February 12, 2010