Electronic thermostat for boiler. General questions about repairing storage water heaters What is a thermostat in a water heater

A water heater thermostat is a special regulator that automates the operation of the boiler. Only this unit “knows” what temperature the water should be heated to and when to turn off the boiler from the network. Therefore, the thermostat not only controls, but also automates the operation of the water heater.

In addition, this block is a kind of “fuse” that saves not only the owner’s wallet, but also the integrity of the water heater itself and the structure being serviced. After all, extra “degrees” are not only extra “kilowatts” that increase the electricity bill. Overheating can “burn out” not only the water heater, but also the building itself where it was installed.

In short, a thermostat for a water heater is a mandatory component that must be present in every boiler. After all, without such a device, any boiler is just a huge “boiler” built into a storage tank. But such a combination does not guarantee either effective work device, nor the safety of the owner.

Therefore, in this article we will look at the operating principle, typical range and methods of replacing thermostats for boilers.

How does a thermostat work?

A tubular electric heater - heating element - with a thermostat for a storage-type water heater reduces the energy intensity of such a device, ensures the safe operation of a pressure tank and automates the entire process of operating the boiler.

Such results are explained by the operation of only one component of the boiler design - the thermostat.

After all, this element functions as follows:

• When the water is heated to the “required degree,” the temperature relay of the regulator opens the contacts of the tubular electric heater.
• After the temperature in the storage tank decreases, the relay “turns on” the contacts and the heating element begins to heat the water.

As a result, the boiler stores a “reserve” of water heated to the desired temperature. Moreover, in an empty boiler tank, the relay should turn off the power heating element, triggered by the temperature of the heating element. Therefore, this element is mounted on the same console with the electric heater.

In addition, the thermostat does not allow the water to boil too much. for a long time, increasing the pressure in the tank. That is, this regulator also works as a fuse, preserving the integrity of the water heater and the life of the boiler owner. After all, the steam formed after the liquid boils can rupture the boiler body, turning a peaceful water heater into an almost military explosive device.

Typical types of thermostats?

Modern boilers use three typical types of regulators, namely:

This is the cheapest and, until recently, the most common type of regulator. Such a thermostat operates on the basis of thermal expansion of a 40-centimeter rod, the dimensions of which increased as the water temperature increased and decreased as the liquid cooled. Moreover, the “increased” rod turned off the power to the heating element, and the “reduced” rod turned on the heating of the water. The first regulator similar type There was a thermostat for the Thermex water heater. However, such a device did not serve as the standard for thermostats for very long. It became clear quite quickly that when submitting cold water in the boiler tank, the rheostat rod decreases in size, activating the heating element to boil already decently heated water.

Therefore, rod rheostats are gradually going out of use, remaining on the market only as a spare part for older boiler models.

The cost of such a thermostat is 400-1500 rubles.

for a storage type water heater, this is a more advanced type of rod detector. This regulator operates based on the same thermal expansion. Only in this case, it is not the rod that changes in volume, but the liquid sealed in the tube, “pressing” the on/off switch of the heating element.

With the help of such a design solution, it is possible to eliminate the problem of “zeroing” the signal from the thermostat sensor in the case of cold water being supplied to the tank. Therefore, all budget boiler models are still equipped with such devices.

The cost of a capillary regulator is up to 3,000 rubles.

This is the most advanced model of the regulator, equipped with two sensors that monitor the water temperature and monitor the fact that the heating element is overheating. The electronic regulator works based on changes in sensor resistance under the influence of increasing temperature.

Moreover, by controlling the dielectric properties of the active element of the sensor, you can control the operation of the boiler, “programming” heating and cooling with an accuracy of a couple of degrees. As a result, electronic versions of the thermostat ensure maximum energy efficiency of the boiler.

Having purchased a water heater with electronic thermostat, you will save on your energy bills. However, the side regulator is not cheap.

For example, for electronic thermostats for Ariston you will have to pay up to 9,000 rubles.

Replacing the water heater thermostat

If the water heater is under warranty or your manufacturer has offered a fairly long period of free service, then it is better to leave it to professionals to replace the thermostat.

If the warranty and free service period have already expired, then you can try replacing the thermostat yourself.

To do this you need to do the following:

• Disconnect the boiler from the network.
• Shut off the “cold” pipeline, stopping the water supply to the heater tank.
• Drain the water from the boiler by opening the “hot” valve of the nearest tap.
• Remove the bottom cover of the housing, exposing the mounting pipe of the heating element.
• Dismantle the pressure ring of the heating element.
• Remove the thermostat sensors and remove the control unit.
• A “fresh” thermostat is installed in place, selected according to the boiler’s data sheet or the manufacturer’s recommendations.
• Reinstall the pressure ring and cover.

Finally, close the tap, turn on the cold water supply, check the tightness of the joints and plug in the boiler.

The thermostat for the water heater is important element boiler devices. The main task of the device is to maintain a given temperature regime heated liquid, and for some models it must be maintained during an emergency shutdown of the electrical appliance in the event of a malfunction. Recommendations regarding the selection and installation of such a device will be discussed in this article.

Peculiarities

The thermostat is responsible for the safe operation of the water heater and turns off the heating element when the temperature reaches the set value. If for some reason the thermostat is missing or faulty, then when the temperature, and therefore the pressure inside the sealed housing, increases, an explosion may occur. Therefore from correct installation and the functioning of the thermostat depends on the safety of others. Modern models are equipped with an emergency shutdown function for the heating element when there is a low level or complete absence of water in the tank, which is very convenient in case of interruptions in water supply, poor pressure and frequent shutdowns.

The operating principle of the thermostat is quite simple. It consists of opening the contacts of the heating element when the temperature reaches a given point and connecting them when the liquid temperature drops below a given value. Almost all models of thermostats are equipped with an indicator light that shows what state the device is in: a lit light indicates the operation of the heating element, and an extinguished light indicates that the water has been heated to set temperature has occurred, and the boiler can be used.

The desired temperature is set on a special electronic display or using a mechanical switch, depending on the model, and can be changed at any time at the user’s request.

More modern and high-tech devices, in the event of a malfunction of the electric heating element, will instantly disconnect it from the network and prevent damage electric shock while taking a shower with an ungrounded boiler. Also, some models of thermostats are capable of performing their functions even if the electronics fail.

In such cases, an emergency shutdown of the device occurs when the temperature reaches 95 degrees, and in the latest generation boilers - at 105 degrees.

Kinds

Modern boilers, as a rule, are already equipped with thermostats, among which are rod, electronic, bimetallic and capillary models.

A rod thermostat is the most common type of household thermostat and is presented in the form of a small tube that expands linearly as the temperature rises and puts pressure on the switch relay. The reverse process with the inclusion of heating elements occurs when the water in the tank cools and its temperature drops below the specified values.

Among the advantages of models of this type, one can note the low cost of devices; the disadvantages include some inaccuracy in operation associated with the proximity of the device to the cold water supply system, which is why the operation of the thermostat is often not entirely correct. Due to constant cooling, the device does not have time to react to the heating of the liquid and does not turn off the heating element. Therefore, the temperature of water from boilers equipped with rod thermostats often exceeds the set values.

The capillary thermostat is the most modern type of thermostat and is a tube containing a capsule containing a contrast liquid. As the temperature rises, the water puts pressure on the membrane, which, in turn, opens the contacts of the heating element. This type thermostats are characterized by increased accuracy and long service life. The tube containing the cylinder is made of anti-corrosion alloys, and therefore the unit is not susceptible to rust and oxidation. The temperature error of capillary thermostats does not exceed 3 degrees.

The electronic thermostat is equipped with a protective relay that stops the operation of the heater when the tank is empty. The cost of such models is slightly higher than the price of simpler analogues. Thermostats of this type are installed on boilers of famous world brands, and are characterized by high accuracy, reliability and ease of use. Particularly technologically advanced models have the function of programming temperature and switching time.

Bimetallic. If in rod and capillary models the indicator of temperature changes is the liquid in a sealed tube, then in thermostats of this type the role of liquid is played by metal plates. When the temperature changes, the plates change their location and open or close the electrical circuit.

According to their purpose, thermostats are divided into adjustable, protective and adjustable-protective. The former maintain the temperature of the heated liquid in a certain range and operate in automatic mode. Reaching the upper limit of the set value, the relay opens the contacts and water heating stops. Upon reaching lower limit set temperature, the relay closes the circuit, and the operation of the ceramic or steel heating element is resumed.

Safety thermostats are designed to forcefully turn off the heating element when the specified heating parameters are reached. You can only turn on the heater after such a shutdown manually. Typically, such thermostats are installed as a second additional device designed to turn off the heating element in the event of a failure of the main thermostat. The temperature in the protective devices is set at 95 degrees, which prevents the water from boiling and a possible explosion of the boiler. The third type - adjustable-protective - is a device that combines the properties of the first and second types, and is considered the most universal device.

Based on the mounting method, thermostats for water heaters can be divided into mortise and surface-mounted models. The first ones are used for mechanical control, the second - with electronic.

Installation

Sometimes situations occur in which the heating element of the water heater is functioning properly, but the thermostat for some reason has already failed - it does not turn off or does not work correctly. In this case, the purchase of a new water heater can be postponed and limited to self-replacement thermostat. To do this, you should take the technical passport of the boiler and, based on it, operational properties and technical characteristics, select the appropriate model.

For more precise selection you should rewrite all the data from the markings of the old device, and based on the technical passport and these data you will be able to purchase a new thermostat.

The connection diagram and adjustment rules are usually prescribed in the accompanying documentation, so before starting self-installation It is recommended that you read the instructions carefully.

Installing a thermostat with your own hands requires certain skills and knowledge in the field. electrical installation work. It is very important to comply with safety regulations, without knowledge of which work cannot begin. Replacement of the thermostat should only be carried out with a similar one. technical specifications model, use homemade device for installation in a factory-made boiler is not allowed.

At the first stage, you should turn off the power to the water heater and stop supplying water to it from the water supply system. Then you need to drain the existing liquid and remove the bottom panel of the device, thereby opening access to the heating element. After opening the cover, you need to remove the pressure ring and remove the old thermostat along with the control unit.

Next, you should install and connect the new thermostat, put the pressure ring in place and fix the bottom panel. After installation is complete, you need to fill the water heater tank with water, turn on the heating element and check the operation of the new device by setting it to the minimum temperature value.

If the thermostat turned off the heating element after the water had reached the desired temperature, then the installation was carried out correctly and the thermostat is functioning in operating mode. On last stage The thermostat should be adjusted to the required operating parameters.

In order to notice malfunctions in the operation of the device in time and take measures to eliminate them, you should know the main causes of breakdowns and their symptoms. The most common thermostat problems include:

• wear of the copper capillary tube;
• poor interaction between the three-pin thermostat and the heating element;
• failure in adjustment and scale formation on the heating element;
• failure as a result of power surges.

Signs of a malfunctioning thermostat:

• the water in the boiler does not heat up;
• the display shows incorrect temperature values ​​that differ from the actual water heating indicators;
• the thermostat does not turn off the heating element at the set temperature, resulting in uncontrolled heating of water, which can only be stopped by disconnecting the boiler from the network;
• The indicator light does not light up on mechanical models.

The thermostat for a water heater is a fairly important part. It is he who is responsible for maintaining a certain temperature at a constant level. The thermostat for the water heater is capable of slowly adjusting the temperature, and it is also equipped with a device that protects it from cooling and overheating. When the need arises, he turns on and off the type, that is, the heating element.

This device allows the user to set a specific operating mode and also maintains the temperature level in automatic mode. If the water temperature decreases, it turns on the heating element, due to which the temperature rises to a certain specified level.

The thermostat for a water heater has a certain operating principle. It is worth saying that it is similar for all types of water heaters. On the screw with which each thermostat is equipped, a certain required water temperature is set. When the swelling valve is tightened, hot and cold water begins to flow into the mixer system, and then the adjustment process begins. The temperature of the water is measured in the chamber, after which the warm water is mixed with cold water required proportions. When supplying water for mixing, hot water has priority, so it will be supplied until its temperature is higher than the set value. After this, the process of mixing it with cold water. Thanks to this fact, it can be explained that the thermostat for the water heater does not respond so quickly. However, the user usually does not experience any particular inconvenience.

If the thermostat for the water heater is installed in a system where there is no circulation warm water, then it is possible that cold water will enter the incoming stream at initial stage. In systems where there is circulation of warm water, the thermostat adjusts the required temperature in an instant.

Storage and flow units are usually equipped with different heating elements. Typically, heating elements in flow-through models have higher power. That is why the choice should be made only after you have decided on its purpose.

An electric thermostat may have normally closed or normally open bakelite. Often owners of water heaters decide to do-it-yourself repair. The thermostat for the water heater "Ariston" and other companies is electrical part, so it’s worth remembering that different warranties are given for the tank itself and for it. If you need to replace any element of the water heater or have it repaired, you should contact service center or directly to the manufacturer, where you can find out whether it is subject to warranty repairs. It is important that the appropriate thermostat model is available.

If you are wondering where you can purchase this device when yours is out of order, it is worth noting that most companies involved in the production of such equipment provide delivery throughout the country. For example, you can order a thermostat for a Thermex water heater at home. It is easy to replace it yourself using simple recommendations.

The thermostat for the water heater plays the same important role, like a fuse in any electrical network. The user sets the required water temperature in the water heater, and the thermostat maintains it. That is, it allows the heating element to work until the water temperature reaches a set value.

Then the heating element stops working. The water temperature drops (forcibly or naturally) and the thermostat again signals the heating element to begin its direct duties.

Separate, specially designed types of thermostats have additional function– turn off the power supply to heating element in case of breakdown of the latter. This avoids the possibility of electrical shock, which often happens with ungrounded boilers.

Types of thermostats

Today, many types of thermostats have been developed, but if we talk about devices specifically for boilers, the three most successful are:

1. Rod. Such a thermostat is represented by a tube of small diameter (usually up to 10 mm) and short length (no more than 35 cm). The operating principle is based on the elementary laws of physics: when heated, the tube expands linearly, which allows you to press the switch. Such thermostats have long been the most common in boilers. However, their accuracy left much to be desired - when hot water left the water heater, the incoming cold water instantly cooled the thermostat due to the latter’s close location to the cold water supply. Thus, the boiler could work beyond the allotted time, and this significantly affected financial costs.
2. Capillary. A more progressive type of thermostat, also working according to the laws of physics. The tube in which the temperature-sensitive cylinder with liquid is located is usually made of a material that cannot be oxidized over a long period of time. Inside the cylinder there is a liquid that has a different density from water. When heated, the density of the liquid changes, the volume changes accordingly, and the liquid presses on a special membrane, which turns off the power. Such thermostats are more accurate when compared with rod thermostats. The temperature deviation is approximately 3°C.
3. Electronic. More modern type and, accordingly, more accurate. It usually works in tandem with a protective relay - if the boiler is empty when voltage is supplied to the heating element, then the protection will work and turn off the power.

According to another classification, all thermostats can be divided into:

1. Electromechanical and electronic. The first type works due to bimetallic elements, the second - thanks to electronic special sensors.
2. Simple and programmable. In the first type, the temperature is set manually mechanically. The second type is more precise in its work.
3. Overhead and mortise. For boilers, the overhead type is most often used if the control is electronic, and the mortise type if the control is mechanical.

Another interesting option– thermostats designed for indirect heating boilers. Such boilers allow you to heat water using only power for heating device, which means there are significant savings. But circulating in heating system the liquid cannot heat above a given level, while for a boiler the consumer may need a different temperature (and most often this happens). In this case, you should buy a thermostat specially designed for this purpose.

Having carefully studied the articles on self-production, you can try to make a thermostat yourself.

Malfunctions and their solutions

The thermostat for your water heater may fail. Unfortunately, such phenomena are not uncommon, but there is nothing fatal here. Firstly, as a rule, there is no repair - a thermostat that has worked faithfully is thrown away and a new one is bought. Buy the same or with a different resistance - the choice is up to the consumer. Secondly, when correct operation water heater thermostat breakdown can be avoided or, in extreme cases, its life can be significantly extended.

How does a consumer notice a broken thermostat? As a rule, this is the most common method - the water is not heated in the boiler. In this case, there may be either a malfunction of the heating element, or a malfunction of the thermostat itself, or (less commonly) a malfunction of both elements. To check the latter, its resistance should be measured.

If during testing the picture on the display of the test device does not change, you need to buy a new thermostat. It's not that much money, so there's no need to grieve. Another option for testing the thermostat is possible: measuring the resistance when the thermostat itself heats up. If even then the test device does not show any changes, that’s it, now it’s time to go to the store.

How to choose

Typically, a faulty thermostat can be replaced with a similar one in shape and operating principle. However, if it is possible to buy and install another thermostat and there is an urgent need for it, then why not. The main thing is to be able to choose the right device and install it correctly. Although here, too, the consumer can be helped by the Internet or a consultant at the point of sale.

But we should not forget: any independent actions Without certain knowledge and strict adherence to safety regulations, they can lead to a very unpleasant outcome.

It would seem that the heating element or volume should be important in a boiler, but, as it turned out, the thermostat and its role cannot be neglected. By setting the desired temperature and protecting the boiler from overheating, the thermostat is extremely important in the operation of the heating device.

We offer to buy a thermostat for a water heater at a low price. Italian quality, long term services, low price, big choice, any delivery. A thermostat for a water heater, another name for a thermostat for a water heater, is used to maintain a set water temperature by turning on/off the heating element (heating element) in the water heater. And also for emergency shutdown of the heating element in case of its malfunction. Thermostats can be rod or capillary, with or without thermal protection. For a rod thermostat, contacts are provided on the heating element flange, as well as a tube into which the thermostat rod is inserted. On average, the thermostat rod is 27 cm long, but there are thermostats with a 45 cm rod for large-volume water heaters. For capillary thermostat On the flange of the heating element there is either one tube or two - for temperature control and thermal protection. Can be sold complete with heating element and magnesium anode. The thermostats are designed in such a way that you can easily replace the water heater thermostat yourself by purchasing it in our online store. At the same time, you will save money on the services of a master. Any delivery and easy design order. both on the website, by phone, and in the online help chat.