DIY water heater tank repair

In detail: DIY repair of a water heater tank from a real master for the site my.housecope.com.

An electric boiler is an effective solution to the problem of hot water supply for a private house. Such equipment, however, like any other, breaks down periodically.

If serious breakdowns have to be eliminated in a service center, then any more or less experienced craftsman can perform a small repair of the water heater with his own hands.

To minimize problems with the device, you should study its design and principles of operation. Usually, in private households, not flow-through, but storage models are used, which make it possible to use electricity more efficiently. Such a device consists of a heat exchanger tank, inside which a heating element is installed - a heating element, connected to the power supply.

An important part of the device is the thermostat. This element allows you to maintain a constant water temperature inside the storage tank. The water is piped to the heat exchanger. If its temperature is too low (and this is usually the case), then the thermostat gives a signal and turns on the heating element.

The water is heated until it reaches the required temperature. After that, the thermostat works again and turns off the heating element. Hot water is taken from the tank and replaced with cold water, the heating process is repeated over and over. This is a general diagram of the device and operation of a conventional storage water heater.

Flow models are arranged somewhat differently. They do not heat a static volume of water, but a stream. They use more powerful heating elements that start working when the water is turned on and stop when it is turned off. To study in more detail the operation and structure of a particular model, you need to carefully familiarize yourself with the accompanying technical documentation.

Video (click to play).

The heater tank is a sturdy stainless steel container, one or two millimeters thick. No matter how resistant this material is to corrosion, nevertheless, these processes periodically arise and develop, which leads to the flow of water from the device. One of the most common causes of such breakdowns is electrical corrosion.

To prevent it, you need to regularly, i.e. Replace the internally mounted magnesium anode annually. This element is specifically designed to prevent electrical corrosion. Over time, it wears out, and the owners of storage tanks lose sight of replacing this important part.

As a result, the tank, which has served well for some time, suddenly starts to leak. The incorrect state of the magnesium anode can also affect the state of the heating element. The outside of the storage tank is usually enclosed in a metal or plastic housing, and it also has a heat-insulating shell that prevents heat loss.

Damage to the outer shell and insulation is rare, usually due to careless handling of the device. Cracks and chips on the body of the water heater may not disrupt its operation, but this will lead to a deterioration in the properties of the heat insulator, and will negatively affect the functioning of the device as a whole.

Cold water inlet and outlet pipes - for hot water usually do not cause any problems if the installation of the heater is done correctly. Usually, a water heater is equipped with two thermostats, one of which is designed to control the water temperature, and the second monitors the state of the first device.

Sometimes a third thermostat is also used, which determines the good condition of the heating element. In any case, the broken thermostat will have to be completely replaced.There are capillary, rod and electronic types of thermostats. Their design is different, but the principle of their work is the same.

The insulating gasket not only serves to seal the connection between the elements of the water heater, it is also necessary as an electrical insulator. It is recommended to replace this element regularly at every maintenance of the water heater.

The thermostat shows exactly what temperature the water inside the device is heated to. If this element breaks down, the water heater will still perform its functions, although data on the degree of heating will not be received.

Breakdown of heating elements is a typical problem for both flowing and storage water heaters. This element works under high stress and therefore wears out quickly. If the power supply is connected, but the water in the tank does not heat up, most likely the problem has arisen with the heating element.

First, you should check if electricity is supplied to the heating element and the thermostat. In the places where the cable is connected, the presence of voltage is checked with a tester. If there is no voltage, you may need to replace the cable itself or check for a power outage throughout the house.

If there is electricity and the cable is working properly, then problems have arisen with the heating element, which will have to be replaced, or with the thermostat. To figure out what exactly broke, you need to remove the thermostat and check it with a tester. Testing the health of the heating element is carried out as follows. First, the measuring scale of the device is set to the interval of 220-250 V. Then the resistance is measured at the terminals connecting the heating element to the mains.

If there is voltage, disconnect the heating element from the network and check the potential at the terminals of the heating element. Lack of response from the tester will indicate that the device is defective. If there is a reaction, you need to continue the diagnosis. First, disconnect the water heater from the power supply. Then the heating element is disconnected from the thermostat so that the contacts of the heating element remain not isolated.

Tester contacts are applied to them and the reaction is monitored. If it is, the heating element is working, if not, it needs to be replaced. In this case, it does not matter what kind of numbers the tester produces, only the presence or absence of a reaction is important. These troubleshooting methods are suitable for both storage electric water heaters and flow-through models.

To check the serviceability of the thermostat removed from the water heater, you need to set the adjustment knob to maximum and measure at the inlet and outlet of the device. If the needle of the tester remains calm, i.e. its position does not change, which means that the thermostat is faulty and needs to be replaced.

If the arrow deviates, then you need to continue testing. Now you should set the minimum position on the thermostat and attach the test leads of the tester to the contacts. It will not be easy to continue the diagnosis alone, the probes will have to be fixed or asked someone to hold them in the correct position for a while.

After that, you need to take a lighter and heat the tip of the temperature sensor. If the thermal relay is triggered, the circuit will open, and the resistance on the tester's scale will sharply go down, then the thermal relay can also be considered serviceable. If the system does not respond to heating, then this element is damaged and needs to be completely replaced.

Occasionally, the water heater can stop working due to a blown thermal fuse as a result of dangerous overheating of the device. It is enough to correctly adjust the operation of the device for it to start working as usual.

If the check showed that both the heating element and the thermostat are in good order, most likely problems have arisen with the control board. It is almost impossible to repair such an element at home.It will have to be replaced with a new one, and you will have to use the help of a specialist who will help you set up the electronic equipment. Most often, you just need to contact the service center, where the required element will be selected and installed correctly.

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Schematic diagram of switching on a "conventional" boiler

If the problem is in the electronic board, it can be circumvented and the boiler will work. As you can see from the schematic, the board is connected in parallel with the heating element power supply circuit. If you want and have basic concepts in electrical engineering, you can turn it off and connect the circuit as in conventional water heaters.But if you do not have such skills or you doubt the success of your plans, you should not start experimenting.

The circuit for switching on a boiler with an electrical board is indicated by number 6.

Other designations: 1 - control thermostat; 2 - control thermostat; 3 - indicator of turning on the heating element, a light that glows when water heating is turned on; 4 - heating element; 5 - grounding.

The device of instantaneous water heaters is practically identical to that described above. The main difference is the absence of a storage tank and more powerful heating elements. Therefore, we will not consider the units of an instantaneous water heater and will not repeat ourselves.

Heating element for repair of water heaters Real

The water heater is included in the network, but the indicator lamp for the heating element does not shine and the water does not heat up? Then the procedure for determining the malfunction is as follows:

We take a combined measuring device (tester), set it on the voltage measuring scale of 220-250V and make measurements at the terminals of the cable and thermostat connection, if the voltage is normal, we measure the potential directly at the heating element terminals. If the voltage at the terminals of the heating element is normal, most likely the heating element itself is out of order.
We disconnect our water heater from the electrical network and put the tester on the resistance measurement scale (Ohm), disconnect our heating element from the thermostat (in most models, a rather simple procedure - we remove the terminals with wires so that the ends of the heating element are "bare"). We measure the resistance at the contacts of the heating element, while accuracy is not important to us, this is not a motor winding. If the element is working properly, the device will show us a certain amount of resistance, if there is no indication, we remove the heating element and go to the store for a new one, it cannot be repaired. You can find out in more detail how to replace the heating element in a water heater from the article on our website.

This procedure for determining a malfunction of a heating element is identical for all types of water heaters, both instantaneous and storage.

Signs of a malfunction of the thermostat and thermostat are the absence of the heating element turning on in the presence of voltage, as well as if the control thermostat is triggered. To check the operation of the thermostat, we will have to remove it, how - you can find out from the article, which describes the procedure for installing and repairing water heaters, it is on the website.

So, the thermostat was removed. We take the device, put it on the measurement of resistance (Ohm). Set the position of the adjusting knob to Max and measure it on the thermostat contacts (input / output). If our tester does not respond, the element is defective, it cannot be repaired. It will be necessary to purchase and install its analogue.

If the control thermostat is triggered, then the procedure for determining the malfunction is as follows. We put the removed thermostat in the Min position and fix the measuring probes of the device on the contacts, if you are not alone - let someone hold it. Take a lighter and heat the thermostat flask / rod. If it is working properly, the picture will be as follows: the thermal relay is triggered and opens the circuit, the resistance on the contacts should tend to infinity, i.e. such as if the probes of the device are spread apart. If this does not happen - the thermal relay is scrapped, we go to get a new one, because this item cannot be repaired.

The most common malfunction, in addition to the electrical components of the boiler, is a leak. There may be two reasons:

tank leak;
leak from under the flange, which secures the heating element.

The reasons that caused the tank to leak can be: lack of grounding (which accelerated electrical corrosion), lack of proper maintenance, natural wear and tear.

It is not possible to repair the tank for the following reasons:

the outer casing and the tank are practically inseparable, dismantling, so that it is almost impossible not to damage the shell;
the inner tank is usually made of stainless steel with a thickness of 1 - 2 mm or in more expensive models made of copper, in rare cases it is made of plastic. There is very little you can do with the latter. You can still tinker with a copper tank and try to solder it, but, as a rule, such tanks are very durable due to their increased resistance to corrosion. Welding such a thin stainless steel at home is not realistic, so you should not waste time and effort.
to everything else, the modern coating of tanks in storage water heaters is glass enamel, which is damaged during welding. It is not realistic to restore it at home, which means that the leak is inevitable in the near future.

The only way out of this situation is to replace the internal tank with a new one if your model allows such a replacement and, moreover, if you find an analogue. But it will be easier to buy a new water heater.

If a leak is detected from under the flange, then there are no particular difficulties for repairing the Termeks water heater, or any other. It is enough to drain the water from the water heater, remove the gasket and visually determine its wear or damage. We take it with us and go shopping in search of a similar one. Changing and using the boiler further. By the way, Onyx offers pipeline parts, including steel flanges, at reasonable prices.

These are the main malfunctions of electric water heaters. As you can see, flowing ones will have less of them, but it also costs more.

Poor water quality is considered to be the main cause of boiler breakdown. Because of this, scale forms on the surface of the heating element, the inner walls of the tank are susceptible to corrosion, which in the future entails more serious consequences and expensive repairs in the service center. In addition, the water heater may stop working due to improper connection to the power supply and the hot / cold water circuits.

As for the latter, when connecting the boiler, it is imperative to install a safety valve between the branch pipe coming out of the tank and the cold water supply pipe, which will protect the tank from rupture during a water hammer. You should also make the connection according to the instructions and, no less important, do not confuse where-what is connected. Sometimes situations arise that, if installed incorrectly, the water heater does not collect water. Please note that you should not panic in this case. It is better to look again at how to properly connect the equipment to the pipes and, most likely, you will understand why your water is not collected.

So that you understand how to repair a storage water heater in different conditions, then we will separately consider how to repair all possible breakdowns with our own hands.

If the boiler does not heat the water to the required temperature, but still makes noise when turned on, it means that scale has formed on the heating element, which you need to clean yourself. This is not difficult to do, you just need to disconnect the equipment from the network, drain the water from the tank and disassemble the case to remove the heating element. You will not have any difficulties with disconnecting the plug from the outlet, but draining the water can make the repair a little more difficult. Immediately we recommend watching a video lesson, which shows a simple method for solving this problem:

After you empty the tank, you will need to disassemble the boiler yourself. To do this, carefully disconnect all fastons connected to the thermostat and unscrew the screws, which are usually 6 pieces.

During the removal of the heating element, a little more water will pour out, which remains in the tank. It is recommended to clean the heating element itself immediately, before it is wet and the scale deposits have not hardened. We recommend using special cleaning agents that can be sprayed onto the heater. After a while, the deposits are effortlessly scraped off with a wooden spatula or even a blunt knife.Also, for repairs, you can boil the heating element in a bucket with the addition of special acid to the water, which will effectively solve the problem. To get rid of limescale for sure, we advise you to use fine-grained emery paper ("sandpaper") to clean the tubes to a metallic color.

Simultaneously with the repair of the boiler, which heats the water for a long time or weakly, it is recommended to replace the magnesium anode, which protects the tank from corrosion. To do this, dismantle the worn out rod and purchase exactly the same one in order to replace it yourself!

After that, you need to assemble the boiler in the reverse order and check whether it was possible to repair the weak heating of the water. Do not forget that first of all you must fill the tank completely with water, then connect the plug to the mains and start.

We draw your attention to the fact that there is a situation when the boiler does not heat the water, because the heater is broken. In this case, self-repair is that you need to ring it with a multimeter, setting the resistance measurement mode. We will tell you about this below!

If the light on the boiler is on and the water does not heat up, then it is likely that the heater, which we talked about above, is not working. It is quite simple to check it at home, you need to install the tester probes on the contacts of the heating element and see the resistance on the display. With a working heater, the resistance can vary between 0.4-0.7, as shown in the photo below. If you see "1" on the display, then there is a breakage and you need to replace the part with a new one, because it is almost impossible to repair it.

By the way, if the boiler beats with current or when it is turned on, the RCD is turned off by itself, then the cause of the breakdown, again, is in the heater from which the leak occurs. You can check the malfunction by connecting one probe to the contact of the heating element, and the second to the tube itself. You will see “1” on the display, the part is in good order and there is no need for repairs, a minus value or too large - replacement is required. In more detail about how to check the heating element with a multimeter, we talked in a separate article.

Another reason why the boiler does not heat the water or, on the contrary, heats up very much, is the failure of the thermostat. You can check it in two ways - with a tester or a lighter. Everything is clear with the tester, you need to act according to a similar method, but as for the lighter, everything is more interesting here. First, dismantle the thermostat and press the button on it (it is circled in the photo below). After that, the copper contact of the thermostat must be heated. If after some time the button returns to its original position (knocks it out), the thermostat is operational. If the thermostat does not work, you can repair the boiler that does not turn off or does not turn on by replacing this part with a new one. I would also like to note that there is no need to drain the water to replace the thermostat on the water heater. It is enough just to disconnect the equipment from the network and disconnect all the supplied wires.

Also, sometimes there is a breakdown - the temperature is not shown on the display of the water heater or the display does not work at all. In this case, check all the elements of the circuit and if you do not find an open circuit, most likely the control unit has broken. You will not be able to repair electronics with your own hands in the absence of experience and knowledge, so you will have to take the electric water heater to a service center for repair.

If you notice that water is dripping from the boiler, it is not always possible to repair it yourself. It is good if the cause of the leak is the wear of the seal on the flange. In this case, the gasket must be replaced with the same size, which will allow the breakage to be repaired. The situation is much worse if the water heater leaks due to the wear of the tank itself. Some advise to glue or solder the holes, but, as practice shows, after a short period of time you will still have to say goodbye to the boiler, becausesuch leak repair methods are extremely short-lived.

That's all I wanted to tell you about DIY boiler repair. We hope that now you know what to do if an electric water heater is leaking, does not heat the water well or does not work at all. These devices do not have many problems and you can get rid of them by timely maintenance of the system. At least once a year, check the non-return valve and clean the heating element so that malfunctions bypass you!

It will be interesting to read:

If an electric boiler breaks down in your apartment, then it is not at all necessary to call the master - you can figure everything out on your own, having straight hands and the simplest tools. If you call the master, his services will cost a round sum. In the end, storage water heaters have a simple design, so that self-repair of the boiler will not cause any difficulties.

Here is a list of the main boiler failures: