Skip to Content

How Do Water Heaters Work?

How Do Water Heaters Work?

When wintertime rolls around, it’s a good idea to think about routine maintenance on our homes. One of these crucial steps is the water heater.

If we take a look at the different types of water heaters, there are quite a few out there. When you’re choosing a new water heater for your home it’s essential that you understand those differences and how water heaters work. This will also help when it comes time to perform maintenance on them.

Do you find yourself asking, “How do water heaters work?” Well, we’re here to explain it in detail. Let’s begin!

How Do Water Heaters Work?

When we talk about types of water heaters, they are primarily classified based on fuel and whether they use a tank.

In terms of fuel, the two types of water heaters are gas and electric. Water heaters can also be classified as a tank water heater and tankless water heater. Lastly, there are hybrid water heaters and point-of-use water heaters.

All these water heaters will be discussed further, along with how they work. But before going into the detailed working of the water heaters, let us first take a look at the parts that make up the water heater.

  1. Flue pipe or gas chimney: This is present in gas-powered water heaters and helps in heating the water surrounding it. Along with this, it also helps in getting rid of all the toxic gases produced.
  2. Drain Valve: This is the valve that comes into play when the heater needs to be drained for cleaning purposes.
  3. Draft Diverter: This element of the water heater diverts all the gases produced into the flue pipe so that they can be easily exhausted out.
  4. Insulation: The tank-type water heaters have this layer that keeps the heat bound to the tank structure to prevent any thermal loss.
  5. Thermocouple: The best thing about the gas-powered water heaters is the thermocouple. It is a component included in the burner part of the water heater that causes the gas valve to shut off if the flame of the burner is blown out.
  6. Elements: In electric water heaters, the metallic elements that are used to heat up the water are known as elements. They are mostly made of nickel and stainless steel and do not corrode easily.

Other than these, there are many other important elements inside the water heater. They will be briefly discussed in the workings of the water heaters below.

How Tank Type Water Heaters Work

How Tank Type Water Heaters Work

The tank-type water heaters are the ones that can store hot water for later use. If we want to talk about the working of the tank-type water heaters, here’s how the process works.

  1. To begin, cold water is brought into the water heater through the dip tube.
  2. As soon as the water starts filling inside the water heater, the gas burner or the electrical heating rods inside the heater start heating the water. In the case of electric supply, water inside the heater is heated by the electrical rods when the water level rises. For gas, the burner heats up the gas chimney by producing toxic yet hot gas. The toxic air is moved outside of the chimney, which heats the water surrounding it through heat conduction.
  3. When hot water is required, it is pumped out through the heat out pipe of the water heater after rising to that level.
  4. As soon as the water level falls inside the water heater, the dip tube fills the heater with cold water again.
  5. Now, the whole process repeats again.
  6. To prevent the build-up of excessive pressure inside the heater, a pressure relief valve is provided that automatically opens when more than the required pressure is built up. The pressure valve acts as a piece of safety equipment in the overall working of the water heater.
  7. These heaters also have an adjustable thermostat that can be used to set the temperature at which they want to heat the water. You need to be cautious while setting the temperature of the water heater, as if the temperature is not set to a particular limit, the heater might get damaged prematurely. Also, if you need to save more on electricity bills, make sure you follow the manufacturer’s guide for setting the temperature. It is recommended by most of the manufacturers to set the temperature of the water heater to 120°F for maximum savings.
  8. Apart from these, there is also a sacrificial anode rod that is made from magnesium or aluminum. This rod is very useful as it is used to protect the interior of the water heater from corrosion. It corrodes itself to save the water heater.

This is the overall process of tank-type water heater working. The tank-type water heater can store 20 to 80 gallons of water. If you are buying a new one, a 40 to 50 gallon version should be enough for your entire family and all of your hot water needs.

How Tankless Water Heaters Work

Tankless water heaters don’t have any storage tank and provide instant hot water at just the time you require it. Let us take a look at the working of the tankless water heater.

  1. The tankless water heater sits idle until the time hot water is needed.
  2. As soon as the hot water tap is opened to get the water, the water heater starts drawing cold water into the unit.
  3. The flow sensor inside the water heater activates the heating element of the water heater. It can be the electric heating rods or the gas burner of the water heater.
  4. The heating rods or the gas burner inside the water heater heat up the heat exchanger.
  5. The cold water flowing inside is passed through the heat exchanger, which leads to heating of the cold water.
  6. After heating, the hot water is fed to the water tap or appliance for use.
  7. This process goes on until the faucet is turned off. As soon as it is turned off, the water heater stops immediately.

So, what is the best thing about this type of water heater? The tankless water heater heats the same amount of water at a better efficiency compared to the tank water heaters! In the case of tankless water heaters with a gas burner for water heating, the gases produced are exhausted through the sealed vent fitted in the water heated.

The tankless water heaters have an upper hand compared to the tank water heater, because tankless water is simpler in function. Along with this, you can get instant hot water whenever required, unlike with the tank water heater. The best thing about the tankless water heater is that it lasts up to 20 years – a much longer time than the tank version.

Yes, it will be a bit costly for you to buy a tankless water heater upfront, but it will be worth that investment in the long run.

How Hybrid Water Heaters Work

GE GEH50DEEDSR GeoSpring Hybrid Electric Water Heater

A hybrid water heater is a device that uses hot air from the surroundings to heat the water inside it. If the demand for water is urgent, it switches to the conventional electrical heating process. The working of a hybrid water heater proceeds as follows.

  1. A hybrid water heater has a pump on the top of the tank that features a compressor and evaporator coil.
  2. Opposite to a refrigerator, a hybrid water heater takes in heat from the air surrounding it. The heat is fed to the cold water through the coils in the storage tank and the cold air produced inside the pump is exhausted.
  3. A hybrid water heater also has electrical heating elements that come into play when the requirement of hot water is urgent.

The best thing about the hybrid water heater is that it uses less power than conventional water heaters. Though the initial cost of a hybrid water heater is high, the benefits and savings are also greater.

How Point-of-Use Water Heaters Work

Point-of-use water heaters are heaters that can be easily installed in a small area, like near a sink or shower. The major benefit of this kind of water heater is that you don’t have to wait for the hot water after opening the tap. As soon as you open the tap, hot water will be supplied on the spot. As a result, you save both time and energy.

The heat loss in the case of point-of-use water heaters is nearly zero, as all of it is delivered at the hot water tap. They also have a maximum life of up to 25 years, which is longer than the other water heaters discussed so far.

Overall, this water heater is best among all, but may not suffice your needs. It’s often used for washing dishes in the sink. Just remember, before installing it, make sure that there is a GFCI electrical outlet nearby.

Types of Water Heaters Summary 

Well, we have studied the working of almost all types of water heaters now. It should be pretty clear to you now what parts are in a water heater and what they do. It is not always easy to keep track of all the parts while using the water heater.

After studying how water heaters work, it is essential to know how to keep them working smoothly like this for a long time. To do that, the best way is to learn how to maintain your water heater.

Maintaining a Water Heater

To keep your water heater working for a long time without issues, you need to keep all parts of the water heater maintained.

It’s possible to maintain it yourself if you have advanced skills, or you can just call a professional. If you are getting it maintained or serviced for the first time, it is always better to call a professional.

No matter what type of water heater you own, it’s important to perform maintenance once at least per year. Let’s go into more detail about how to maintain your water heater.

The Internal Structure Of a Water Heater

The life of a water heater highly depends on its internal structure and components. There are many internal components in the water heater that need careful analysis every time you clean it. For example, one of the essential parts of a tank water heater is the sacrificial rod.

Sacrificial Rod: This rod usually needs to be changed every five years. To check the rod, unscrew the opening of the heater and look for the rod. If you are not able to locate the rod, refer to the manual for your water heater.

You’ll want to check if the rod looks corroded. If it does, change it. If not, check the time for which it has been used. If it is more than 5 years, change it. If less than that, you can keep it after cleaning.

Water: The working of the heater is also highly dependent on the water used in it. Make sure that the water you use is free from any minerals. Water with a lot of minerals is known as hard water. To keep the working of the water heater smooth, you may need to add a water softener to the heater.

While maintaining the water heater, if you ever find the color of the water to be brown or rusty, it may be time to change your water heater. In order to be sure, fill the water heater and drain it two to three times. If the water is still rusty, you should replace the water heater.

Check Pressure Valve

Check Pressure Valve

The pressure valve is the most important component of the water heater. It has the most crucial function in the water heater. As we discussed before, the pressure valve controls the pressure inside the water heater. In the case of high pressure build-up inside the water heater, it automatically opens and releases the extra pressure to prevent damage.

That’s why it is essential to maintain the pressure release valve regularly – you should expect to perform a regular maintenance check on the valve yearly at a minimum.

Check the pressure relief valve: Checking the valve is a pretty easy task. All you need to do is gently lift the pressure relief valve. If water is released from the discharge pipe, the valve is fine and does not need replacement. On the other hand, if the pressure relief valve is faulty, water will not be released from the discharge pipe.

Replace the pressure valve: If you find out that the pressure valve needs replacement, replace it by following the mentioned steps:

  1. Turn off the water supply to the water heater.
  2. Drain the water heater.
  3. Remove the discharge pipe by unscrewing it properly.
  4. Unscrew the faulty valve.
  5. Before attaching the new valve, wrap the threads of the valve with sealant tape to prevent leakage.
  6. Screw the new valve properly to the water heater and check if it works properly.

Check Sludge Build-up

The term sludge means the sediments that get deposited at the bottom of the water heater. This sediment deposition can lead to various issues for your water heater. The water heater may sometimes produce banging sounds after use. This banging sound is due to the solid masses crashing against the wall of the water heater. They are generated by solidification of the sediment deposits inside the water heater.

In short, the sediments need to be removed from the water heater to prevent damage in the future. To remove these sediment deposits from the water heater, you just need to drain the water heater 2 to 3 times with water. By the third time, there should be no particles in the water. If there are, you need to get it checked by a professional.

All these aspects need to be carefully examined when you’re performing a maintenance check on the water heater. You can try to do it by yourself, but if you have a new water heater and are maintaining it for the first time, it is better if you get it maintained by a professional.

FAQs on How Water Heaters Work

Here are some frequently asked questions that might help you with the working of the water heater.

1. What are the various safety features in the water heater?

There are plenty of safety features in a water heater. The key elements that protect the water heater are the thermostat, pressure valve, and thermocouple, among many others. They prevent the water heater from various issues like bursting from pressure build-up or overheating.

2. What is a porcelain enamel glass lined tank?

There are plenty of safety features in a water heater. The key elements that protect the water heater are the thermostat, pressure valve, and thermocouple, among many others. They prevent the water heater from various issues like bursting from pressure build-up or overheating.

3. What is the warranty period on your water heater?

The warranty period can vary a lot from model to model. Usually, the inner tank has a warranty period of 5 to 10 years. Along with this, it is important to note that all parts of the water heater don’t have the same warranty period. For example, the heating element may have a warranty of just 2 to 3 years after purchasing your new water heater.

4. Will my water heater consume a lot of energy?

The energy consumption of the water heater depends on various factors like the type of water heater, the star rating, and more. The heater with a star rating of 4 to 5 will consume less energy. On the other hand, point-of-use heaters and hybrid water heaters consume relatively less power.

Final Words

To summarize, it is easy to say that there are many components with a crucial role in the working of the water heater. Depending on the type of water heater you have, the parts also vary with their functionality.

Along with learning how do water heaters work, it is also essential to have knowledge of how to maintain the water heaters for smooth functioning for a long time.

What’s why it’s important to review various maintenance tips and methods for a water heater. All these maintenance tips should be taken care consistently, as they will decide how long your water heater lasts.

If you are looking for a new water heater, make sure you consider all the important aspects like:

  • Where do you need a water heater?
  • What kind of service will it require, and what will it cost you?
  • Do you have enough space to adjust the water heater (especially for point-of-use heater near the sink)?
  • What are your water requirements?

After finding answers to all these questions, you’re ready to get a new water heater!