The magnesium anode, also called sacrificial anode, plays an important role in preserving the integrity of the water heater tank. In fact, the tank (ranging from 8/20/40/60 liters and more) tends to accumulate electrical potential which discharges into the materials of the boiler, corroding it.

A boiler anode is a metal component used to protect the inside of the boiler from oxidation and corrosion. The anode is usually made of zinc, magnesium, or aluminum and is placed inside the boiler.

The anode works like a magnet for oxygen ions in the water, attracting them to itself and preventing them from reacting with the boiler’s metal components. In this way, the anode prevents boiler corrosion and prolongs its lifespan.

The boiler anode needs to be checked and replaced periodically as it gradually wears out during the boiler’s use. The replacement frequency depends on the type of anode and the water conditions in the area where the boiler is used.

It is important to keep the boiler anode in good condition to ensure safe and efficient boiler operation. If you suspect that your boiler’s anode is damaged or needs replacement, it is always advisable to contact a specialized technician for boiler maintenance and repair.

Not replacing the anode

In the long run, it significantly compromises the boiler with the risk of replacement and leaks. A worn-out anode, if the cap is brass, degrades taking on a pink color (Degradation of the brass cap). In the case of a worn-out anode, the leak almost always occurs near the central area (where there is less thickness due to the threading accommodation). In the worst case, the same anode thread dirties the female thread, necessitating re-threading to insert the new component.

Blocked Anodes

Otherwise, once the anode is finished, more likely with galvanized caps, the cap gets welded to the housing collar. It is not recommended to use larger wrenches to apply more force, as this could break the collar and require the entire boiler to be replaced.

How often the anode should be replaced

The lifespan of the magnesium anode depends on the environment where the boiler is installed. The average lifespan is two years, but in some areas, in proximity to railways or high voltage poles, the lifespan can be as short as one year.

Another factor that affects the lifespan of the magnesium anode is a poorly calibrated water softener. If the softener provides water with too low a hardness, the anode's lifespan can be significantly affected.

Sizes and Quality

On the market, you can find anodes of different qualities and sizes, in addition to the metal used, these can have:

  • Anodes prepared for a 3/4-inch cap, with an M8 threaded core
  • Anodes prepared for a 1/2-inch cap, with an M6 thread
  • Brass M8 caps for 3/4-inch
  • Galvanized M8 caps for 3/4-inch
  • Brass M6 caps for 1/2-inch

Problem of air in hot water

Regarding the degradation of the anode inside the boiler, a consequence is the production of air which is especially noticeable in the morning when the boiler is off for the production of domestic hot water. This is due to the early consumption of the anode. If the deterioration is too rapid, the type of anode can be changed by choosing, for example, magnesium anodes or electronic anodes, which have slower or no consumption and solve the air accumulation problems.

Magnesium Anode

magnesium anode in storage water heaterThis is the first choice during regular boiler maintenance, the magnesium anode is the most common component to protect the tank from corrosion.

When the magnesium anode is inserted into the boiler, it becomes the most reactive element in the oxidation and corrosion reaction, preventing the boiler's metal from corroding. Magnesium chemically reacts with water, attracting oxygen ions and preventing them from combining with the boiler’s metal components.

As water flows through the boiler, the magnesium is gradually consumed and the anode needs to be replaced periodically. The lifespan of the magnesium anode depends on the water conditions in the area where the boiler is used and the type of boiler.

The magnesium anode is generally considered an effective and economical solution to protect the boiler from corrosion, although it may be subject to problems such as the formation of sediment or scale deposits. For this reason, it is important to perform regular boiler maintenance and replace the magnesium anode when necessary.

Aluminum Anode

aluminum anode in storage water heaterThis type of anode has a longer lifespan thanks to the use of aluminum, and it is used as the first solution against air or early degradation of the magnesium anode. The lifespan of this replacement can exceed 6 years and is already a good investment compared to its cheaper counterpart.

Aluminum is also capable of greater flexibility, allowing this replacement to be inserted fully in length without touching the walls of the coil.

Electronic Anode

electronic anode for storage water heaterIf the effects of the degradation of the previously mentioned anodes are too rapid, or if you want to invest in a definitive solution for the anode, you can purchase an electronic anode, which, thanks to a probe, is capable of discharging the currents collected in the tank through the ground. Therefore, it is important to have a good ground connection. Although the costs of this solution are higher, the device pays for itself over time.

An electronic anode is therefore a metal component used to protect hydraulic equipment from oxidation and corrosion. Unlike the traditional anode, the electronic anode works through an electronic control system.

The electronic anode uses an electrode system to create an electromagnetic field around the equipment to be protected. This electromagnetic field prevents the formation of rust and corrosion, preventing the oxidation of metals.

The electronic anode consists of two main parts: an anode electrode and an electronic control system. The electronic control system regulates the amount of electrical energy supplied to the anode electrode, based on water conditions and the needs of the protected equipment.

The electronic control system of the electronic anode is able to constantly monitor the water quality and adapt the amount of electrical energy supplied to the anode electrode based on the needs. In this way, the electronic anode is able to provide continuous and precise protection against corrosion.

The electronic anode is considered a more advanced and efficient solution compared to the traditional anode, as it provides more effective and precise protection against corrosion, as well as requiring less maintenance and replacement.