Electric heating elements: basic types, principle of operation and installation features

Recently, electric heaters have become a familiar accessory both for residents of multi-storey apartments and for owners of country cottages. This equipment provides residents with the required amount of water required for domestic use. Electric heating elements for water heaters are the main structural elements of any device, it is due to them that water is heated.

Types of structures

Structurally, the heating element is a tubular electric heater. The heating element of the heating element can be made of high-carbon steel, stainless steel or copper.

In each of this tube, which is a kind of shell, there is a wire spiral. With the help of it, electricity is carried out.

According to the principle of operation, all heating elements can be divided into two main types. In one case, heating heating elements are made in a traditional form - almost in the same way as in a conventional electric kettle. Devices are called "wet" because the element is in contact with heated water. And when the equipment is closed, the tube is in a special flask that heats the liquid. The element, therefore, does not come into contact with water, therefore this type is called "dry".

To find out which heating elements are best used for boilers, you need to briefly familiarize yourself with their main design differences.

Open views

A characteristic feature of these elements is that they are located in direct contact with the water heated in the storage tank. The tubes are filled with quartz sand, which is a good heat conductor. The main element of such a heating element is a thin nichrome wire in the form of a spiral.

Most often, copper or stainless steel is used in the manufacture.

Open heating elements are divided into groups according to certain technical characteristics:

1. Absence or presence of an anode socket. If the heating element is equipped with a nut, then it may not have an anode attachment or, in addition, a fastening thread is located on the flange.
2. Taking into account the method of fastening, heating elements are nut and flanged. In this case, the latter can be made using casting or stamping.
3. In shape, open heating elements can be straight or curved. The shape depends on the type of storage tank for heating water.

Heating elements for boilers quickly heat the liquid, in addition, they have a low price. But such devices have much more disadvantages. The main disadvantages are:

• high level of danger;
• the rapid appearance of plaque (especially given the quality of water in the central highways);
• high power consumption;
• short service life.

Closed options

This is a special type of heating element, which is insulated with a ceramic bulb. This flask is subject to stringent strength requirements. During the manufacture of the flask, magnesium silicate or steatite is used, while the heating element itself in this case is made of stainless steel.

That is why the water in the closed type boiler is heated by the heat transfer of the jacket.

There are several advantages in this case. First of all, due to the closed design, these devices are absolutely safe, since the possibility of a short circuit is completely excluded. In addition, such types of heating elements:

• easy to operate;
• easily repaired;
• have a fairly long operating time;
• economical.

The flange, like the accumulator itself, in these water heaters is protected by an enamel coating that prevents the formation of limescale. It is for this reason that the operating time of "dry" elements is approximately 3 times longer than that of "wet" ones.

On the negative side, it can be noted that all steatite heaters are not universal. They are manufactured separately for any type of boiler, and it should be borne in mind that, if necessary, the element must be replaced only with a similar one.

Connection methods

It should be noted that heating elements for boilers can be mounted in the device either one at a time or several at once.

The more heaters there are, the higher the power of the equipment. But the power indicator will also depend on how all the elements are connected to each other - this connection can be one- and three-phase.

Parallel connection

This connection option must meet certain requirements.

The basic rules are as follows:

1. The voltage both in the electrical network and in each individual element must be the same.
2. To determine the total power of the boiler, you need to add up the power of all installed elements.
3. If, for some reason, one of the heating elements breaks down, then the circuit will continue to work. In this case, the only thing that needs to be done is to change the broken element.

To find out the total power of the network, it is necessary to divide the voltage by the total resistance of the network. And the total resistance can be determined by the formula that is applied during the parallel connection of individual resistances.

Sequential inclusion

The second option is daisy chaining. Wherein it is necessary to follow the principles of work:

1. If one of the heating elements breaks down, then the operation of the entire network will be interrupted.
2. To find out the total resistance, it is necessary to add up all the resistances in the network.
3. The total voltage cannot exceed the total voltage of all heating elements.

Combined method

Taking into account this scheme, different connection options must be used in several sections of the electrical circuit. Quite often, the combined method is advisable if it is impossible to purchase heating elements of the required power. In this case, the available heating elements are installed, and the required value is achieved using various connection methods.

Possible malfunctions

According to experts, the period of operation of heating elements in boilers is approximately 5 years. Hard water is the most common cause of equipment failure. To lengthen the service life of the device, regular prophylaxis is needed, which consists in cleaning the anode and directly the heating element from the scale that has appeared.

The main sign that the heating element is broken is the lack of heating and the activation of automatic protection. There are several options for checking an element for its performance:

1. With a simple light bulb. To do this, you need to assemble a serial network, which consists of a light bulb and a heating element, connected to electricity. If the light is on, then everything is in order with the heating element and it does not need to be replaced.
2. Using a tester, you need to determine the resistance of the heating element. If the resistance is zero, then the heating element must be changed.

The elements must be replaced with devices that fully correspond to the capacity of the boiler. The steps in this case are as follows:

1. First you need to turn off the power and water supply. After that, the liquid is drained from the storage tank and the top cover of the device is removed.
2. Then you need to check the input terminals with a phase meter for the absence of current.
3. The bolts that fix the heating element directly are unscrewed, then the wiring cable is removed.
4. It is imperative to determine in what state the contacts of the new heating element are. They must be dry.
5. Then, simultaneously with the heating element, the anode is also replaced, which is intended for protection.
6. During the installation of a new element, only high quality seals are used without any defects.
7. Installation is carried out in the same way, but in reverse order.
8. At the end, the storage tank must be filled with water, and the remaining air must be drained from the tap, which is designed to supply hot water. After that, it remains only to connect the water heater to the mains and check it for operation.

Popular manufacturers

Today, heating elements are presented on the domestic market in a fairly large assortment, while there is a huge selection of various manufacturers. All devices differ both in their design and in their main purpose and average market price.

Ariston Products

This is an Italian manufacturer that makes heating elements from a special alloy of chromium-nickel and copper. The heat output of the equipment is increased by the use of a special brass flange. The approximate power will depend on the specific model and will be in the range of 1-6 kW.

Models of heating elements with an installed thermostat enable the consumer to independently set the required temperature (no more than + 95 ° C). When this indicator is reached, the device automatically turns off. If the temperature drops by more than 7-8 degrees, the heating element resumes its work, so the water in the storage tank will be constantly hot.

Domestic products

"Termex" has been known on the market for over 60 years. Magnesium anodes of this company are made of a special alloy, due to which the performance of the elements is doubled. The outer shell can be either copper or stainless steel. With the help of reliable protection, a long operating time is ensured. All devices are low-power, which makes them quite economical.

Boilers Electrolux

The company from Switzerland is characterized by the excellent quality of manufactured water heaters. Its products are distinguished by the fact that they are equipped with two closed heating elements at the same time. This results in a high heating rate. Protective measures prevent the formation of limescale. These measures include:

• a thermostat that turns off the equipment when it reaches + 80 ° С;
• special glassy enamel coating;
• protection from moisture and dust;
• magnesium anode;
• thermal insulation of the storage tank.

Advantages and disadvantages of water heaters with heating elements of both "wet" and "dry" type. It is more reliable to buy equipment with a "dry" heating element, since it is characterized by a long operating time, the device does not depend on water quality and is resistant to corrosion.

Choosing premium devices is optional, you can purchase devices from a lesser known manufacturer. The most important thing is to regularly inspect the heaters and diagnose problems in a timely manner.