Water Heater Galvanic Corrosion

A typical 40 gallon water heater showing the threaded copper to steel tank connections.

Water heater galvanic corrosion.

There are different types of corrosion but when we re talking about a residential water heater it s the corrosion that occurs because of the mix of oxygen and water in contact with metal. With brass connected to galvanised pipe you can get some galvanic corrosion. This type of corrosion can affect various parts of your water heater. Galvanic corrosion is defined as an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact and immersed in an electrolyte.

There are three main causes of galvanic corrosion. A typical example is the water heater where the anode rod is made of magnesium a water tank is made of steel while the electrolyte is water. In galvanic corrosion one of the metals corrodes much faster than the other. A water heater is designed to resist corrosion through a number of methods.

It s the same thing that occurs in a simple battery. The water heater s electrical heating elements consist of a steel interior with a copper sheath. Electrolysis and corrosion occur when the inner steel and the outer copper become wet and with continued corrosion the heating element will simply fail to work. The most common occurrence is at water heaters where copper water pipe connects to the steel tank of the heater.

Direct current being transferred onto to a water service line from the secondary electrical ground. The primary causes of galvanic corrosion. When two different metals are in contact an electrochemical process called galvanic corrosion can take place. The interior of its hot water tank is lined with glass.

With an electric water heater galvanic corrosion is often a problem as the heating elements inside the water tank are made of steel that has a copper sheathing. Galvanic or electrolytic corrosion occurs when two different materials are in contact via an electrolyte. There is something called a dielectic union which i ve never needed to use. Galvanic corrosion dissimilar metal corrosion is an electrochemical process in which one metal corrodes preferentially when in electrical contact with a different type of metal and both metals are immersed in an electrolyte such as water.

When these combine you get this thing called galvanic corrosion. Dissimilar metals being connected to each other such as galvanized pipe and copper tubing. In galvanic corrosion the greater the difference of electro potentials of the metals the faster corrosion takes place. Plumbing involves metals and water.