Boilers of indirect heating

The availability of hot water supply, without a doubt, increases the comfort of the life of a modern person. And if it is easy to get hot water in a city apartment, it is enough just to open the tap, but for private houses it often turns out to be a problem. Various heating devices are used to provide households with warm water. One of them is an indirect heating boiler that works together with the building’s heating system.


  1. This option of the heater is the most optimal in the presence of a single-circuit boiler operating on natural gas or solid fuel.
  2. Thanks to its installation, the residents of the house can receive heated water in large quantities without interruptions. At the same time, warm water will flow to several points at once.
  3. Such a boiler does not put a load on the power grid and saves electricity.
  4. With a large heat exchanger area and high boiler power, the productivity of such a boiler is quite high.
  5. The water from the heating system does not come into contact with the water that comes from the boiler for sanitary needs. Water with a minimum amount of salts circulates in the heat exchanger.
  6. A boiler operating on the principle of indirect heating can use other energy sources in addition to a gas boiler for its work.


  1. The equipment has a rather high price, if compared with ordinary storage devices.
  2. Such a boiler, especially if it has a large capacity, takes up a lot of space.
  3. When a large volume of water is heated in the boiler, the temperature of the coolant in the heating system drops slightly.
  4. Placing the device is not profitable if the house is heated using an electric boiler, as well as in the case of low water consumption.

Comparison with other types of heaters

Unlike a double-circuit boiler, the combination of a boiler with a single-circuit boiler is more expensive, but ensures the supply of water without temperature changes and interruptions.

While the instantaneous heater can supply water only to 1-2 points of water separation, the device with indirect heating is much more productive and can provide heated water to the entire house.

In addition, the temperature of the water from the flow device is unstable, for example, if you turn on the faucet for washing dishes and the shower in the bathroom at the same time. As for the differences from storage boilers, the indirect heating device is distinguished not only by higher productivity, but also by lower electricity consumption.

Principle of operation

Heating enters the cold water boiler according to the principle of heat transfer. Hot water flows through the heat exchanger located inside the tank, which is heated by a single-circuit boiler or another energy source. The heat from this coolant passes through the walls of the heat exchanger to the cold water that enters the device from the water supply. It gradually heats up and is removed from the boiler through the outlet pipe.


When buying an indirect heating boiler, the following parameters of this equipment are taken into account:

  • It is selected depending on the needs of the family.
  • Installation type. Some models of boilers can be hung on the wall, others are installed on the floor.
  • Dimensions and weight. It is important to take them into account when choosing a place where the equipment will be installed.
  • Ten’s presence and power. The heater is needed to use the boiler in the non-heating season, and its power affects the rate of water heating.


With one spiral heat exchanger

Inside such a boiler there is a single heat exchanger represented by a spiral. It can either be located at the bottom of the water heaters sacramento tank or be evenly stretched inside the tank.

tank-in-tank device

Such a boiler does not have a coil, as it is replaced by a slightly smaller capacity installed inside the tank. Cold water enters this container, and water heated in the heating system circulates its cavity, which transfers its heat to it.

With two heat exchangers

The design of such models provides for the presence of two tubular heat exchangers. One of them is connected to the boiler and receives coolant from it, and the second can be connected to any other heat source, for example, to a solar collector.

Popular volumes

100 liters

Boilers of this capacity are very common and are most often bought when there are 2-3 people in the family. Water from such equipment is enough for washing dishes and a daily shower for all household members. If someone from the family wants to take a bath, there will be enough water for only one person, but it will remain for other household needs, and there will not be enough for a second bath.

150 liters

This is one of the most requested volumes when buying an indirect heating boiler. Water from such a device is quite enough to provide for a family of 4 people. This volume is sufficient to wash oneself, wash dishes and take both a shower and a bath.

200 liters

This volume of the boiler is enough to provide a private house in which 4 or more people live. Water from such equipment will be enough for several bathrooms, as well as for kitchen needs. All family members can wash their hands and dishes, and take a shower, or bath.

Equipment with such a volume is in demand for large houses where several families live. Water from this boiler will be enough for all household needs. With such a heater, all household members can wash and wash dishes without any restrictions, and also do not have to choose between a shower or a bath.

With electric tan

A boiler that, in addition to being connected to the heating circuit, is equipped with a Ten is called a combined boiler. Such a device works all year round, while in the winter the coolant enters it from the heating boiler, and in the summer the water is heated from the tank, as in a conventional storage device.

The power of such a Ten is 2-6 kW. Its inclusion is regulated by a thermostat when the device detects a decrease in the temperature of the water inside the tank. Some models have a Tena switch-on timer, which allows you to save electricity.

Tips for choosing

The first question that is important to solve when choosing an apparatus with indirect heating is the required volume of the boiler.

To calculate the required capacity of the device, you need to know that one person spends:

  • for washing – approximately 5-15 liters of water;
  • for taking a shower – about 60-90 l;
  • per bath – from 160 to 200 l.
  • on average, 20-25 liters are used for washing dishes.


A magnesium anode is installed inside the indirect heating boiler, designed to protect the tank and internal elements of the device from corrosion. It should be replaced regularly, as it is “eaten”. Instead of such an anode, you can resort to the use of cathodic protection, but for this the boiler must be constantly connected to the power grid.


Blogger By Passion, Programmer By Love and Marketing Beast By Birth.

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button