Most of us never give a second thought about the components of our hot water heaters. Their mysterious workings remain unseen and disregarded. However, the longevity of the water heater actually depends heavily on the workings of a single component - its anode.
Find out why your hot water heater anode is important and how to do some very simple checks to get the absolute maximum performance out of your heater to virtually double its lifetime.
Anode Anatomy
The anode is a steel core wire which is surrounded by metal--either magnesium or aluminium. It is screwed into the top of the water tank and its job is to protect the tank from rusting.
The life of the anode depends upon a number of factors including the quality of the tank construction, amount of usage, water quality and temperature.
Anode Workings
When the metal tank is filled with water an electrochemical process is initiated. The exposed metal of the tank begins to corrode as it begins the process of returning to its natural state as an ore.
However, each metal has different reaction rate to this process. Magnesium and aluminium being highly reactive makes these metals particularly effective for work as anodes.
The anode protects the less reactive metal surface of the tank by acting as a sacrificial anode. The magnesium or aluminium in the anode gives itself up to protect the metal of the tank.
How to Check Your Anode
Preliminary steps
- Close the shut off valve
- Turn off the gas of electricity supply to the heater
- Turn on a hot water tap in the household to relieve pressure
- Open the valve on the bottom of the tank and drain off a few litres of water
Remember you are dealing with hot water so proceed with caution.
Removing the Anode
Anodes tend to become frozen in place by corrosion so an impact socket wrench is highly recommended to add some muscle power.
The anode is usually located at the back of the tank close to the outlet flue.
Release the anode by loosening the hex head which is often hidden beneath a plastic cap. A spray lubricant applied and left for a few minutes to soak in will help the process along.
Assessing the Anode
After successful removal check for signs of wear. If most of the metal is still intact it should last for a few more years. However, if it seems to be splitting or much of its core wire is exposed it will need replacing.
Your replacement rod will simply screw into the opening left by the old one. Use some teflon tape to help secure it in place.
Sourcing Replacement Rods
You have the choice of either aluminium or magnesium anodes when you buy a replacement rod.
It is generally thought that magnesium anodes are superior in performance.
- Magnesium generates stronger currents so it is more efficient and able to offer improved performance against rust.
- Aluminum on the other hand tends to collect a larger build- up of corrosive materials that collect on the bottom of the tank.
However, aluminium is cheaper and is frequently used for that reason.
It is also worth noting that you can source a flexible anode that allows you to bend it as you install it. This overcomes the problem in situations where access is restricted and it is difficult to fit in a rod of around a hundred centimetres without sufficient working room.
Anodes are readily available on line if not stocked at your local plumbing supplies store.
Understandably, you may be a little hesitant about your ability to change an anode or you may not want to mess about with gas, electricity or water pressure. Fortunately you can rely on the professionals to do a quick check of your anode and install a replacement if needed.
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