For efficient transformation of electric current into thermal energy heating element is used.
Tubular electric heater is used in modern electric boilers, stoves, electric kettles and other devices that provide electrical heating.
Heat is released due to the heat inside this device nichrome thread, which runs exactly in the center of the tube and is reliably isolated from its surface by a layer of dielectric. Ceramics are usually used as an insulating layer, which transfers heat well without letting in electricity on the outer surface of the heating element.
Advantages and disadvantages
Among the few disadvantages of these devices, we can only highlight: not a very long service life and the impossibility of repair if the heating element burns out.
There are many more positive properties:
- High efficiency.
- Reliability.
- Electrical safety.
- Possibility of equipment.
Varieties
There are tens various shapes, power and heating environment.
The most popular varieties:
Tubular
This design is most widespread in water heating devices. The cost of such elements is quite high due to the materials used in their production. of stainless steel and nichrome.
Device data when high-quality manufacturing can last more than 10,000 hours.
finned
The design of the heating element differs little from the tubular one. The only difference is the perpendicularly located stainless steel fins relative to the main heating device. This design allows you to increase the power of the heating element due to a larger heated surface area.
Block of electric heaters used in installations high power, for example electric boilers.
The use of such heating elements allows you not to worry about complete failure of the heating device. In the event that one burns out a heating element, the boiler only slightly loses power and continues to function in this state until such time as possible without the threat of defrosting heating system replace the failed heating element.
Cartridge
Such a heating element is convenient in that it allows you to replace a damaged device even in a water heater filled with liquid in a matter of minutes without depressurizing the tank. Like a cartridge, this element is inserted into a metal shell, which in turn is already in contact with the heated medium.
The cost of such devices is slightly higher due to more precise processing of the heated surface.
Heaters of this design are used primarily for heating liquids.
The thermostat not only allows you to set the required temperature, but also when set to maximum heating does not allow the liquid to boil, eliminating the possibility of such a heater exploding.
A Question of Choice
Eternal heating elements do not exist today. When heated, the metal gradually becomes thinner at the bending points and sooner or later the filament breaks. Premature failure of heating elements may be associated with overheating; water heating heating elements that are turned on when there is no water in the water heater often burn out in this way.
Choosing the right heating device will allow the device to last long years without replacing the heating element.
High price is not always a criterion the right choice, there are numerous cases where expensive heating elements from a well-known company worked for no more than 6 months.
Selection rules:
- It is necessary to check that the seller has documents for the goods being sold. The guarantee that the manufacturer gives for the heating element is also an indirect sign of the product High Quality. The higher guarantee period operation, the more reliable the purchased product.
- The correct choice of heating elements cannot be made without selecting the heating element according to power, which is necessary to heat the liquid. If the heating element is less powerful than necessary, then the water will not heat up to the temperature for which the water heater is designed. In the case where an element consumes a large electrical power, excessive load on the wiring may occur. Therefore, when replacing this element, it is necessary to select a heating element only of the power for which this water heater is designed.
- When choosing, you must choose modern devices turning off the electric current supply. The most advanced thermostats in this regard are those that use electronics to regulate the heating temperature. Devices in which the working element is solid heat elements that expand when heated are outdated and have a limited working life.
- The correct choice is only possible if the device can easily fit in the tank, otherwise the installation of such a heater will not be possible.
- You should be especially careful when choosing a heating element that will be installed directly into the heating radiator. In this case, in addition to the size, important criterion element selection are the number of the thread on which this device will be installed.
- If you need to replace a burnt heating element, then when going to the store to buy a new element, you should take the burnt one with you and choose exactly the same size and markings.
Installation and replacement
For installation work, you will need the following tools:
- Phillips and slotted screwdriver;
- pliers;
- spanners;
If the heating element is being replaced, then before installing new element, dismantling of the failed heating element is carried out.
Before starting this operation, it is necessary to turn off the power to the water heater by removing the plug or turning off the circuit breakers on the central electrical panel if the boiler is connected directly.
Installation is carried out in the following sequence:
- The tank must be washed thoroughly from the accumulated scale and wipe it with a rag.
- The new heating element is installed in this way so that the rubber gasket adheres evenly to the surface of the parts being connected. All threaded connections must be tightened to the required torque. When the heating element is installed, electrical wires are connected to it.
- Then the bottom cover is installed and the boiler is filled with water. If there are no leaks, then you can connect the water heater to the electrical network.
If you need to install a heating element in a heating battery, then in the lower part heating device The plug is unscrewed and the heating element is installed in its place. The system is then filled with liquid and the heater is connected to network variable 220 V.
Price
Heating element block with Ariston type thermostat (I)
This device has a built-in thermostat that allows you to adjust the operation of the device to heat the liquid in the range of +20 - 80 degrees. Working surface This device is made of copper, which promotes maximum efficient heat transfer.
Price – 1000 rubles.
This device can be used both in factory water heating installations and in self-made water heaters. The heating element body has a hole for installing a thermostat, which is purchased separately.
Cost – 1200 rubles.
TENB-9 stainless steel 220/380V
Heater block for water boiler. On one flange of this device there are 3 elements with a total power of 9 kW. The heating elements are reliably isolated from each other, which allows you to regulate the heating power of the liquid. The heating element is made of stainless steel, this protects the heating element from corrosion and allows the equipment to operate without failure for up to 5 years.
Price – 1300 rubles.
- You should not try to repair a burnt heating element - this is a useless exercise. If the heating element fails, it must be replaced with a similar device.
- The heating element for water must be immersed in liquid during operation. Otherwise, the device will very quickly fail due to overheating.
The thermostat is designed to maintain a set temperature by controlling heating (cooling) elements.
These devices come in several types, ranging from simple mechanical ones to electronic multifunctional and even smart devices. 
The principle of operation is that the device has an external temperature sensor that reports the temperature to the device environment. A thermostat is used to maintain and adjust a given limit. Used to maintain various devices such as: refrigerator, heated floor, water heating or heaters, incubator, greenhouses, etc.
Connecting a heating element with a thermostat
Let's consider the principle of operation and the connection diagram.
They are used for boilers and heating boilers. We take a universal one for 220V and 2-4.5 kW, a regular one, with a sensitive element in the form of a tube, it is placed inside the heating element, in which there is a special hole.
Here we see 3 pairs of heating elements, six in total, you need to connect as follows: set zero to three and phase to the other 3. We insert our device into the open circuit. It has three contacts, in the photo below you can see one in the center at the top and two at the bottom. The upper one is used to switch to zero, and which of the lower ones to phase should be checked with a tester.
We set the regulator to minimum - we ring the lower left with the upper with the tester - there is a sound signal, but not on the second, now we increase the degree and the tester rings the lower right with zero. This means that the power comes to zero (upper) and goes from it to the heating elements, i.e. are powered up. And the lower left pin can be used for an indicator to indicate when the heating element is turned off.
The storage electric water heater consists of the following elements:
- tank or housing;
- thermal insulation made of polyurethane;
- internal tank - a container in contact with water, covered with glass porcelain, enamel or stainless steel;
- magnesium anode that protects against corrosion;
- heating elements (heating elements);
- thermostat for temperature regulation;
- relief valve for relief overpressure in the tank.
The thermostat, like the heating element, are important components electric water heaters. The heating element heats the water, and the thermostat is responsible for maintaining, adjusting and heating the water to required temperature. In addition, it is also responsible for the safety of the device, since it turns off the heating element when the water temperature becomes critical and steam begins to form.
Types of thermostats (thermostats) and operating principles
Typically used in water heaters the following types thermostats:
- rod (bimetallic);
- capillary;
- electronic.
The operating principle of the capillary thermostat is pneumatic. The pressure inside the gas flask in which the thermostat is enclosed varies depending on the temperature. The change in pressure is transmitted to the electrical contacts through a pneumatic relay along the capillary.
An electronic safety and control thermostat is a more expensive thermostat for a water heater. The water temperature in the boiler is inversely proportional to the resistance of the electronic sensor. It is by this principle that the temperature of the water heater is controlled and adjusted.
Briefly, the operating principle of any thermostat can be formulated as follows:
- The required temperature level is set (lever, button, switch).
- The thermostat measures the water temperature and turns on the heating (heating element) if necessary.
- After desired value temperature is reached, the thermostat breaks the circuit and turns off the heating element.
- As soon as the water cools down, the thermostat for the water heater is activated again, the circuit is closed and the water is heated.
Submersible heating element - heating element
Such elements are a thin tube of copper or steel with a high-resistance metal wire and magnesium oxide inside for electrical insulation. It is mounted in the same flange where the thermostat for the water heater and the anode (magnesium) are located. Submersible elements reliably protected from water ingress, and their operating temperature reaches 300-400 degrees. Heating elements are distinguished by shape, power, size. The elements are connected to one or three phases.
Advantages of submersible elements:
- optimal combination of price and quality;
- high efficiency and reliability.
The design of the element is similar to the submersible type, with the only difference being that the body of such a heating element is made of refractory ceramic tubes. Mounted ceramic heating elements in an enamel housing with a thermostat and anode.
The advantages of such elements:
- quick and convenient replacement of elements in case of breakdown, which does not require draining the water;
- the enamel coating of the body completely protects against corrosion;
- resistance to scale formation, since the large area of the elements prevents them from overheating.
One of the most important parts for a water heater is the thermostat. It is the thermostat for the water heater that maintains a constant water temperature, protects against overheating, and, if necessary, performs operations to turn the water heater off and on. It is the thermostat that makes it possible to set temperatures and maintain automatic modes.
Basic principles of thermostat operation
Every water heater thermostat works on the same principle, regardless of the manufacturer. The thermostat is equipped screw design , at which the temperature required by the user is set. After tightening the shut-off valve, cold and hot water begins to flow into the water heater, after which the adjustment processes begin to work.
For getting desired temperature in a water heater has an advantage hot water. It flows until it reaches the specified parameters, only under this condition does mixing with cold begin. Depending on the type of water heater - instantaneous or storage, the power of the heating element is selected. Most often, it is in flow heaters it has great power.
How to choose the right thermostat
When selecting a heater or additional installation thermostat, it should be remembered that on heating tank and the thermostat itself has different warranty conditions. This is due to the fact that many skillful water heater owners, when different types in case of breakdowns they take care of do-it-yourself repair. Most frequent breakdowns thermostat:
- copper capillary tube very sensitive to mechanical damage; once it fails, it cannot be repaired, it should only be replaced with a new one;
- poor adhesion of the electrical connectors of the thermostat and heating element;
- insufficient amount of hot water relative to the total capacity of the water heater may be due to incorrect heating element adjustment;
- too hot water indicates a failure of the thermostat control structure;
- if scale has formed and its amount exceeds permissible norm, the thermostat will turn on and off very often;
- failure of the electrical components of the water heater is most often caused by constant voltage drops in the network; to ensure operational safety, the source must be identified uninterruptible power supply or voltage stabilizer.
If you need to replace a thermostat for a water heater, you need to know what types exist:
- Rod thermostat– consists of a steel rod, which is designed to be placed in the heating element tube. Depending on the power and volume of the water heater, the length of the thermostat rod is determined. It ranges from 25 to 45 centimeters.
- Thermostat, which consists of a polyester housing. It has a built-in switching device (thermal regulator). Such a device is called capillary. The principle of its operation is based on the volume of expansion fluid in the capillary tube. The expansion fluid acts on the membrane installed in the thermostat and switches the electrical contact.
- There are two types of electronic thermostats: control thermostat and safety thermostat. Their operation is the same as that of fuses, which have a certain resistance.
The thermostat for a water heater is precisely the part that is the basis for the entire functioning of the boiler. With correctly selected technical specifications and all operating conditions are met, the water heater will last for a long time no cleaning or damage.