fix copper-galvanized corrosion?

[taihaiteki]

How do I remedy a copper-galvanized corrosion problem on my water heater connections? I put the water heater in with a friend's help about 3 years ago. Now please see photos of corrosion between the flexible copper connectors and the fixed galvanized pipes (both hot and cold). Photos are at:

Do they sell some kind of spacer that can be put between the two and is corrosion-neutral or something? What do I want to buy and install to stop the corrosion? Thank you.

[Greg O]

You need to look for a "dielectric union", any home store, hardware store that sell plumbing will have them, Greg

[Jimi]

[Jeff Wisnia]

Dielectric unions are no good for that application because the tank and the house pipiing are connected together by code required grounds already, completing the galvanic cell's connection.

You can get some improvement by using insulated nipples which create a much longer insulated water path between the copper and steel piping, so the current density causing the corrosion of the steel parts is reduced by the current having to flow through a higher resistance water path.

The Rheem water heater company has a technical paper stating this.

You'd be far better off replacing all that copper stuff with galvanized right to the tank, then you won't have any significantly dissimilar metal joints and no galvanic corrosion problems. Plus, you'd get rid of a pretty raunchy looking piece of "modern art" there.

Jeff

[hwm54112]

Replace the galvanized reducer coupling with a cpvc coupling or combination of fittings