This water heater found in a MI home had no
dielectric unions. The severe corrosion has resulted from the contact between galvanized pipe and copper flex connectors.
"Galvanic" corrosion occurs between any two dissimilar metals in contact with each other and water.
Galvanic corrosion is, in fact, defined as an electrochemical reaction of two dissimilar metals in the
presence of an electrolyte, typically water, and where a conductive path exists. This very small current flow
causes the corrosion of the least corrosion-resistant (active) metal to increase and corrosion of the more
corrosion-resistant (inactive) metal to decrease. Since current flow and dissimilar metals are involved, this
form of corrosion is called galvanic, or two-metal corrosion. Corrosion progressively destroys the metal,
causing weakness, which can lead to failure. One of the more effective methods of controlling corrosion is
preventive, such as using
dielectric couplings.
It's obvious this water heater was leaking before it
was winterized, a replacement tank is needed.
Photo provided by Randy Aldering
Housesmithe Home Inspection
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