In household storage boilers A capillary thermostat is used as a temperature sensor - the device is quite unpretentious, however, in my case, after three years of use, it died out for a long time. The search for a similar one in our area was not successful, so the question arose about an electronic regulator - as simple as possible and, if possible, reliable. I started surfing the Internet, and one of the first I came across was a well-known scheme:
In preparation for its practical implementation, I discovered an article on the Internet: “A simple thermostat based on an adjustable zener diode TL431,” which was accepted for implementation.
My modified version:
Differences from the original scheme:
- Thermistor – rated 22 kOhm.
- Variable resistor – 33 kOhm. Since I don't need a wide range of the regulator, I deliberately moved it towards a wider range. high temperature, receiving in return smoothness of adjustment.
- Instead of the 7805 stabilizer, its Russian analogue KR142EN5A was used.
- Tumblr manual mode replaced by the KM1-1 button.
- The complete starting block is used as a load switch
- IEK KMI-22560, in the housing of which the circuit was mounted.
- Power supply 220/12V - converted from a power supply unit from Sega. I stabilized the 12-volt voltage, so to speak, with a reserve; theoretically, you can do without it. If you decide to leave it, then instead of a transistor and a zener diode you can use KR142EN8B. Alas, I didn’t have it on hand.
In place of the “stop” button there is a neon indicator connected in parallel to the contacts of the intermediate relay, signaling the Standby mode. On the front side, through the hole, the KL102 LED is visible - an indicator of power supply to the control board. The SG-5 connector is used to connect 12-volt voltage and a temperature sensor.
Inside view:
A variable resistor installed on the side of the printed conductors simultaneously plays the role of a printed circuit board holder.
Now – about the temperature sensor itself. The fact is that in storage boilers there is a special sealed tube on the bottom side, approximately half the height of the tank (the actual length of the tube depends on the capacity of the boiler). It is into this that the capillary rod of the standard regulator is inserted. I did the following: I took a piece of PUNP 2x1.5 wire, 60 cm long. Having removed the outer insulation at a distance of 45 cm, I wrapped one of the wires with a thin strip of FUM, which is used in plumbing. Next, having soldered the thermistor leads to the conductors and insulated the soldering points, I wrapped the entire structure with FUM - from the thermistor to the rest of the insulation. One edge was treated with tsapon-varnish, and a terminal block was attached to the second:
Having inserted the resulting temperature sensor into the tube, I fixed it at the outlet with electrical tape:
The temperature sensor was connected to the circuit with a shielded wire to eliminate possible interference. Do not forget to also close the contacts that were connected to the old sensor, otherwise the heater circuit will remain open
Assembled view:
Perhaps not entirely aesthetically pleasing, but quite functional. Two months of operation have shown that the circuit operates in normal mode, no trigger effect is observed, and the accuracy of operation is noticeably higher than that of its mechanical counterpart.
When implementing the scheme, I was guided by the principle of “minimal intervention” - i.e. if necessary, everything can be quickly returned to normal. But I don't think I will need it.
Maxim Taranets, Kartaly 2016
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. Thermostat for a water heater, another name for a thermostat for a water heater, is used to maintain the set water temperature by turning it on/off 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 a capillary thermostat, there is either one tube or two on the flange of the heating element - 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 ordering. both on the website, by phone, and in the online help chat.The thermostat for a water heater is one of the components of the boiler protection system (the second is a safety valve). It is needed for convenient operation - thanks to it you can always find out how much stock is currently in the container.
The thermostat also controls the heating process and prevents overheating. If it fails, it needs to be replaced. We can say that this is an element that stops the action of the heating element (heating element) when the temperature approaches established restrictions. In the event of a breakdown, the temperature will begin to rise and enormous pressure will form in it. After some time this may lead to an explosion.
That's why correct operation in general, as well as individual parts, will save your money and ensure safe use. It is for this purpose that this article will reveal the principle of operation, types, technical problems, diagnostic methods and tips for effective operation.
Principle of operation
Externally, they may be very different, but basically their operating principle does not change much. The main part is the heat-conducting rod. It expands when heated and sets in motion a system of contacts, which in turn disconnect the heating element from the network. As the rod cools, its length gradually decreases. Then the thermostat transmits a signal to the heating element, which will soon put the heating element into action again. The temperature that the regulator must maintain is set by the user himself in accordance with his needs.
In short it can be described as follows:
- Setting the desired temperature level using a lever, button or switch
- Measuring temperature and turning on the heating element if necessary
- Upon reaching desired value division turns off the heating element
- after cooling, the thermostat starts working again and heating starts again
Today there are devices that have additional function– turning off the electricity supply to the heating element in the event of a breakdown. Thanks to this, the safety of use is increased and the risk of electric shock is prevented.
Main types
Heating elements come in different capacities. The more powerful it is, the more intensely the liquid inside is heated. Moreover, the thermostat is exactly the part that is the basis. If you have chosen everything correctly specifications and conscientiously follow all the rules for its operation, the water heater will serve for a long time no unscheduled cleanings. So what are they like?
Rod
It consists of a steel tube of small diameter (up to approximately 10 mm) and length (about 25 to 45 cm), which depends on the volume and power of the heater. This thermostat is placed in the heating element tube and it works according to the elementary laws of physics. As the tube heats up, it expands linearly, allowing the switch to be pressed. However, their main disadvantage is inaccuracy and high cost of use. When hot water leaves the tank, cold water entering cools the thermostat very quickly. For this reason, the boiler heats up more than it actually needs, and this increases electricity costs and shortens the service life of its parts.
Rod apparatus
Capillary
This type is considered more progressive. It consists of a polyester body that does not oxidize for a fairly long time. It has a built-in switching device (thermal regulator). Its operation occurs on the principle of the volume of expansion liquid in a capillary tube (the same physical law as in the previous one). The expansion liquid inside the cylinder, which differs in density, changes its density when heated, after which it acts on the installed membrane and turns off the power supply. Compared to rod devices, such devices are more accurate in their readings and, as a result, more economical.
Electronic
Electronic is the most modern type, which means the most accurate and safe.
In turn, they come in two types: safety thermostat and control thermostat. If it is empty at the moment when voltage is supplied to the heating element, then the protection will turn on and turn off the power.
Other types
- Electronic and electromechanical. The first works thanks to special electronic sensors. The second is due to bimetallic elements.
- Simple (the required degrees are set manually) and programmable (higher accuracy).
- Invoices (if electronic control are used most often) and mortise (more intended for mechanical control).
- Designed for boilers with indirect (indirect) heating. They will save you a lot of money because they heat water while using only power for heating device. But the fluid that circulates in heating system cannot heat up above the level that was initially set.
The most common breakdowns
How to detect and eliminate:
- The water is too hot (this may occur due to the failure of the structure that performs the regulating function)
- Failure in copper capillary tube. This part itself is very sensitive to various types of mechanical damage. Unfortunately, it cannot be repaired, only a new one can be installed.
- The adhesion of the heating element and electrical connectors is insufficient.
- The thermostat turns on and off very often (the reason is excessive scale formation, which exceeds the permissible limit).
- The water is not heated enough, although the power of the heating element is very high (this occurs when the adjustment is incorrect)
- Malfunction of electrical components (most often this is due to voltage fluctuations in the electrical network; you need to install a means that will provide uninterrupted power supply or a voltage stabilizer)
Diagnosis of failure and selection of a new device
It is quite simple to detect damage in a timely manner in order to avoid unnecessary expenses and maintain your health. What can be detected even with the naked eye is that the water has stopped heating. To check its functionality and serviceability, remove it from the heat exchanger itself, and then put it to measure resistance (Ohm). A special tester is used for this. If the tester does not show any reaction (no changes occurred on the device screen during testing), then we can conclude that the device is faulty and needs to be replaced with a new one. Thermostats cannot be repaired.
We would like to draw your attention to the fact that any independent actions for the purpose of inspection or repair without the appropriate knowledge, skills and compliance with safety rules can cause injury. It is better to seek help from a specialist.
It is best to choose a new one from the same company. Thus, all their parameters will coincide and function smoothly. The form and principle should be similar to the previous one. It is determined by the temperatures that need to be regulated, the quality of the materials from which the device is made, the brand, manufacturer, etc.
At first glance, it may seem that the heating element plays a key role. Some people think that the most important thing is the volume of the device. But experts say that you should not forget about quality and service rules. Set adequate heating degrees, the power of the heating element, carry out regular checks, and also be attentive to the main “symptoms”. This way you will protect full functionality and make it safer for you and your family. Moreover, the service life household appliances will be extended, and finances will be saved.
The water heater allows you to create comfortable living conditions due to the constant supply hot water.
The main components of any water heater are:
You can find out the price and buy heating equipment and related products from us. Write, call and come to one of the stores in your city. Delivery throughout the Russian Federation and CIS countries.
- outer casing, which can be metal, plastic or a combination;
- internal tank, which is usually made of of stainless steel;
- thermostat / thermostat, which will be discussed below;
Thermostat for water heater
A safety thermostat for a water heater is a device for keeping the water temperature within the specified values. It is called “protective” because its main function is to protect the device from overheating. It regulates the temperature of the water in the tank, promptly starting and stopping the heating process.
In addition to automating work, the thermostat is responsible for the safety of using water heating equipment. Because if the temperature rises, the pressure in the tank will also increase. And if you do not monitor the pressure, the system may explode.
Principle of operation
Each manufacturer equips water heaters different types thermostat, but the principle of operation of the device still remains the same.
The thermostat opens the contacts of the heating element if the water reaches the desired temperature value, and when the liquid cools, the heating element turns back on. This is the principle of operation of the water heater thermostat.
Its task is to control the heating and cooling of water.
A modern water heater thermostat can provide additional signals. For example, if a tubular electric heater breaks down, the next step is to automatically disconnect the system from the power supply. Or, for example, a shutdown will occur according to the same pattern if the heating element fails to cope with its duties due to plaque.
Types of thermostats
Water heaters can be equipped with different thermostats. The main types are rod, capillary, electronic.
Rod thermostat for a water heater - this is the most popular type today. It is a small diameter tube that functions according to the laws of physics. When heated, the tube expands linearly and presses on the switch, and when cooled, it contracts and turns on the heating element.
It has the disadvantage of inaccurate operation, since its location is close to the water supply.
The storage boiler is designed so that when leaving hot water, cold water immediately enters the tank so that the water level is always the same. Since the rod thermostat is located near the inlet cold water, then he has critically little time left to expand to required sizes. The cold liquid quickly cools it, and the boiler functions almost non-stop during its use.
Rod thermostat for water heater
Capillary protective The thermostat for the water heater is more modern solution. It consists of the same small-diameter tube containing a capsule with contrast liquid. Such a thermostat changes its volume depending on the temperature in the heater tank. With a certain heating, water presses on the membrane, which is connected to electrical contacts.
Capillary thermostat for water heater
Electronic thermostat for a water heater it is also considered modern version. For better functioning, it interacts with a protective relay. This makes it possible to switch off the power in an emergency if the water heater tank is empty.
Ariston electronic water heater thermostat
Of course, there are other classifications of thermostats. If we consider from the side of the main control element, we can distinguish electromechanical and electronic devices. If we take the method of indicating temperature as a basis, then there are simple and programmable ones. Surface-mounted and mortise thermostats are distinguished based on the type of installation.
How to check the thermostat
Failure of the thermostat - common reason breakdowns of even the highest quality boilers. You can notice problems yourself, without outside specialized help.
The most common problems associated with thermostats may be the following:
- the copper capillary tube is worn out;
- failure in the settings of the heating element;
- the appearance of plaque;
- malfunctions due to voltage surges;
- poor coordination of contacts between the heater and thermostat.
To check your water heater thermostat you will need a multimeter.
How to check the thermostat of a water heater or how to “ring” the thermostat on a water heater:
- First, find out if the thermostat is working. To do this, remove it and switch it to resistance measurement mode.
- The next step is to set the maximum temperature value and measure the resistance at the output and input contacts of the device. The thermostat design is most likely faulty if the device “does not respond” at all.
- If, nevertheless, the design is working properly and has responded, then you need to move the regulator knob to the lowest setting and reconnect the tester probes to the contacts.
- Finally, use a lighter to heat the thermostat tube. If the system is working properly, then the relay should respond, opening the circuit, and the resistance indicator will jump.
How to choose the right one
It is safe to say that if the thermostat breaks down, it will be simpler, easier and cheaper to buy a new one.
You can select a thermostat for a specific water heater model, taking into account geometric dimensions tubular electric heater, its power, and also based on the volume of the tank of the water heating structure.
But you need to consider the following points:
- When you go shopping, take with you technical certificate water heating structure to show the seller. The seller will help you choose the right one in in this case model and not to be mistaken.
- Do not throw away the relay. It can be useful when choosing an identical device (after all, each has its own marking).
- If you choose a device yourself, then consider the dimensions, current and resistance, as well as performance characteristics.
The thermostat not only keeps the water heater in working condition, but also makes electricity consumption more economical. This is one of the main components water heating structure, so you should pay special attention to it.
It can be used both for heating (as part of a radiator) and to provide the home with hot water. The first thing that needs to be done when putting it into operation is to protect the system from possible breakdown of the electric heater, as well as create conditions for it battery life. A popular method of solving this problem is to use a thermostat for the heating element. This small device, also called a thermostat, can help solve many problems.
Composition of water heating equipment
The simplest water heating or heating element must consist of at least three elements - a water tank, a heating element - heating element, and a thermostat. The tubular heater can be immersed or dry. In the first case, it is made of stainless steel and placed inside the tank. Water is heated by direct contact of water with the heating element.
Dry heating elements are made of ceramic and are located outside the water tank. Heating of the coolant occurs due to the transfer of thermal energy through the wall of the tank. Such elements are easy to replace if they fail.
The thermostat for the heating element is designed to control and maintain the set temperature of the coolant, as well as for emergency shutdown of the tubular electric heater from the network if the boiling process begins (as a rule, this happens when the heating element breaks down).
There are several types of thermostats, each of which is advisable to use with a specific type of tubular electric heating element.
Basic operating principles
Regardless of the design and design, all thermostats operate according to the same scheme. To operate, the thermostat must be built into the tank and also connected to the heating element. The entire temperature control process can be divided into 4 stages:
- The toggle switch sets the required temperature range of the coolant.
- A thermostat for a heating element with a programmed mode measures the degree of water heating and gives a command to turn on the device.
- When the water temperature reaches the set upper heating limit, the thermostat opens the electrical circuit and turns off the heating element.
- After the water has cooled, the whole process is repeated.
It's worth noting that no matter what temperature range you set, the thermostat will turn off the heating element if the water starts to boil. This is necessary to prevent damage to heating equipment.
During boiling, the process of intense vaporization begins. Along with the amount of steam, the pressure inside the tank also increases. As soon as the pressure value exceeds a critical level, the tank will explode. The thermostat for the heating element prevents this from happening by opening the electrical circuit in advance.
Types of thermostats
The operating principle of the device always remains the same. Only the principle of determining the coolant temperature depends on the type of thermostat. According to this, all thermostats are usually divided into rod, capillary and electronic.
Rod devices, as the name implies, have the shape of a rod with a length of 25 to 50 cm. The principle of determining temperature is based on the difference in the coefficient of specific thermal expansion of two metals. The rod thermostat is installed outside the water tank in a special tube.
The capillary thermostat of a heating element for heating water is a hollow tube, inside of which a special liquid is “sharpened”. As the temperature rises, it expands, begins to put pressure on the walls and acts on the membrane, which opens the circuit. When cooling, the reverse process occurs.
The operation of electronic thermostats is based on the ability of materials to change their ohmic resistance along with changes in temperature. As a result, the voltage in the device increases or decreases, which is detected by special sensors and the heating element is turned off or on. Electronic devices are the most complex and expensive, but at the same time the most accurate.
Heating elements with built-in thermostats
A heating element separate from the thermostat is rarely used in practice. As a rule, this solution has proven itself only in water heating boilers. with a thermostat are much more common.
In such “combined” appliances, the thermostat is located in separate tube, and it is easy to replace if broken. When choosing devices in this category, you need to pay attention to the following points:
- Case material. It can be represented by “stainless steel” (the cheapest and most common devices), as well as copper. Copper appliances last longer, but are also much more expensive.
- Power. For a home electrical network, choosing devices more powerful than 2.5 kW is dangerous - there is a risk of overload and short circuit. When using more powerful heating elements, lay a separate power cable.
When choosing a battery, you should not focus on expensive models. Practice shows that the durability of devices does not depend on price. The service life is determined by water hardness, loads and stability of the electrical network.
Areas of application of heating elements with a thermostat
The scope of application of a heating element with a built-in thermostat is quite narrow, due to high energy consumption and short term services. They are most widespread in water heating equipment. This “water tank” is installed in the shower or kitchen and serves as the main or backup source hot water.
Very rarely, tubular electric heaters are used for space heating. In this case, the element is installed directly into the radiator through a special fitting. The main advantages of installing a heating element with a thermostat in a heating radiator are speed. With this simple solution you can very quickly provide your home with a backup heat source.
Features of heating elements for cast iron batteries
Tubular electric heaters for conventional and cast iron radiators there is practically no difference. The only exception is the material of the plug - it must be made of cast iron or an equally heat-resistant material.
In addition, the shape of the outer part of the housing where the thermostat is installed may also differ. In this case, the length of the heating element should be 5-10 cm shorter than the length of the radiator. Otherwise, water circulation and heating cannot be achieved. Therefore, before purchasing, make sure that the heating element with a thermostat for cast iron batteries intended.
Thermostats on the market
Thermostats for heating elements can be called consumables. That is why it often comes separately from the heating element. To replace it, you just need to select a similar device on the market. To do this, find out:
- Dimensions, type and method of fixing a failed device in the tank.
- The maximum current that the new thermostat will have to handle.
The best option would be to purchase the same device that has become unusable. This can be done by contacting the store with a faulty thermostat. In most cases, sellers themselves will select the necessary device for you.
