Electric hot water heaters - Working and troubleshooting

Electric hot water heaters - Working and troubleshooting
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I am sure you enjoy taking a shower in hot water after a hard day’s work. But have you ever thought about the technology that goes behind a typical electric hot water heater. Well surely this is not rocket science and if you read this article with concentration for 5 minutes, I am sure you will understand the basic working theory of electric hot water heaters. This will not only increase your knowledge but also give you a solid background to troubleshoot common problems without having to call your electrician.

Let me also remind you that this article is one in the series of articles designed to give you an insight into the working of simple household items such as the electric doorbell, and common fluorescent tubelight and so on.

Basic Working Principle

If you want to go into the very basic principle, it is simply the conversion of electrical energy into heat through the use of heating element/s to raise the temperature of water to a certain degree.

Obviously this is not much different from a common immersion rod which you can dip into your bucket, plug into the power socket and get going. The only difference is the level of sophistication and slight automation in the geyser.

Of course different heaters of different companies and brands can have slightly different arrangement but the basic concept behind all of them remains the same. You can take a look at the diagram below to understand the construction of a typical heater.

Construction and Working


As you can see from the image, there are two pipelines, one for inlet of cold water and the other for outlet of the hot water. The water tank is fitted with heating element/s which is/are controlled by thermostats. The function of the thermostat is to set the temperature to a certain value so that water is not heated above that value.

The tank is normally covered with some insulating material such as glass wool and entire assembly is enclosed inside a metal casing which can be hanged on the wall or wherever required.

The sacrificial anode is used to protect the tank from corrosion by sacrificing itself and helps to prolong the life of the tank.

Common Troubleshooting

Understanding the working principle of any device is the first step towards common troubleshooting measures. It is not possible to list each and every trouble and its root cause but some of the commonly occurring problems have been discussed.

Warning – Please be warned that electric heaters and similar devices can be dangerous if you try to repair them unless and until you know what you are doing. So I would advice you that if you are having any doubts or not clear about anything, do not try to tamper around with the device. This could not only lead to further damage but more importantly it could lead to a severe electric shock which could be fatal for life.

I will also be posting articles related to common safety measures when dealing with electrical devices and what to do in case you find someone having suffered from a mild or severe electric shock.

In the meantime we will continue with troubleshooting tips in our next article.