Operating Principle No ratings yet.


Operating principle

The main elements of water heater construction are a tank, which receives cold water, and the heating element (heating element), which transfers the thermal energy of the liquid. The physics law makes the heated water rises upward of the tank, where it is taken by a branch pipe. In order to control the temperature of the fluid inside the tank is installed temperature sensor.

The capacity of heating elements is comparable to the power of a heating element installed in ordinary electric kettles, and it is 1.5-2.5 kW. It takes near 2.5 hours (2 kW of heating elements) for the heating time of 80 liters of liquid to 75 degrees. In order to connect the device to the network is used a regular plug.

Types of water heaters

When choosing a water heater, it is necessary to consider a number of constructive features of the appliance, listed below.

The form

There are four main types of devices by form:

Cylindrical, which is the most common option with a wide range of functions;
Rectangular, which can be placed in the corner areas of walls, cabinets or niches;
Narrow (slim), which is a variation of cylindrical boilers, the cross section of the body of which has a small diameter;
Flat, which is a variation of rectangular devices, in which the dimensions in length and height far exceed the width. The body of such devices contains two sections, each of which has its own heating element. This design feature does not affect instrument performance. It is installed in those rooms where it’s important to save the space.


This parameter is highly important, because it directly determines the price of the device, and the amount of heated water. The following features must be taken into consideration for choice:

the number of points of fluid intake;
the number of users;
is the appliance connected to the bathroom?

Based on the needs per person (at least 32 liters of water per day), should be selected the boilers with the following tank volumes:

  • 50 l – for 2 people;
  • 80-100 – for a family of 3 people;
  • 100-120 l – for 4 people;
  • Up to 150 liters – if the appliance is used for the bathroom.

Installation method


Modern devices can be installed in the following ways:

Such devices have a smaller mixing surface of the liquid, therefore, provide equally heated liquid. The disadvantage is that there is need in a lot of free space;
This is a more expensive option, which takes less space for installation. The main disadvantage is small temperature drops due to the increased area of  the mixing mirror;
There are also universal models that can be installed horizontally or vertically. For correct operation with a horizontal installation, it is necessary to follow the requirement for the location of nozzles: cold – from below.

The water heater is attached to the load-bearing wall with a solid base, since the appliance filled with liquid has a rather large mass.

Heating element

There can be two types of heating elements in modern appliances:
  • Wet” – directly in contact with the liquid. It’s made of copper. In contact with the liquid is scaled, which leads to a decrease in the energy efficiency of the device. Magnesium anode is used to slow down the formation of scale devices. Disadvantages of a “wet” heating element: need in frequent maintenance, replacement of the anode, accelerated corrosion of the hull (tank);
  • Dry” – located in a protective body (flask or steel enameled tube). Advantages: lack of scale, increased heating area, ease of replacement of the element, increased service life of the tank. The main disadvantage is the price, which is 150% -200% higher than the price of the device with a “wet” heater.

Water heaters produce heating fluid for a relatively short period of time. Some models contain two elements of different power to work in different modes. In case of need for rapid heating, they can function together.

Material of tank

The service life of the device as a whole depends on the internal tank resource. If there is defect, this part almost can’t be repaired. Modern devices contain a tank, which is made of two main types of material:

Stainless alloy. Service life – up to 10 years. The disadvantage is a high probability of corrosion processes in the weld;
Plain steel with enamel coating. The protective layer has properties similar to steel, and therefore is not damaged by the temperature effects.

The most important characteristic of the tank is the thickness of walls, which is usually not indicated in the technical documentation. The parameter is determined by weighing the instrument. A tank with a capacity of 80 liters and a mass of 25 kg has 2 mm thick walls.

Thermal insulation

The efficiency of energy use of the device is directly related to the quality of the insulation of the tank, since storage devices provide not only heat, but also temperature preservation for a long time. The proper thickness of the thermal insulation layer is from 35 mm and more.

Type of control

The accuracy of the temperature setting is determined by this parameter. There are the following types:
  • Mechanical, with a hidden regulator, located under the hood (low-end models). Temperature control requires removal of the bottom cap of the tank;
  • Mechanical with a turning mechanism and a thermometer. Used in low-cost models. Advantages: simplicity, reliability, durability. The disadvantage – no possibility of fine adjustment;
  • Electronic with display and mechanical or touch buttons. Advantages: adjustment accuracy, automatic diagnostics, preset modes. Disadvantages: high price, sensitivity to voltage drops (voltage relay helps to solve the problem).


The service life of the device depends on compliance with the rules of service, under which the tank and the heating element are cleaned and the anode is replaced. In boilers with a “dry” heating element, the anode is changed once every 2 years, with “wet” – once a year.

It is recommended to install a filter with a replaceable cartridge, which must be replaced at least once every 6-12 months, when installing the device in the cold water supply section of the pipeline.