Recirculation of hot water through a boiler

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The water pressure in the boiler itself may not be sufficient to provide hot water. To recirculate hot water through the boiler, it is necessary to properly install the DHW system with the installation of the circulation pump.

In large holiday homes specialists recommend installing a hot water supply system (DHW) centralized method of heating water, through a gas and electric column (you can also use single-circuit gas boiler). In this case, in order to provide the necessary supply of hot water, an indirect-heating boiler must be built into this system.

The volume of the boiler is calculated taking into account all the people living in the house (for a family of 4 people, it is enough to have a boiler for 100-150 liters.). The water in the DHW system is heated by means of a heat exchanger, which is connected to a heating source (boiler, column).

The DHW system boiler has several inputs and outputs. The peculiarity of indirect heating boilers is that a coil is installed in it in the form of a spiral tube made of metal, through which hot water from the boiler passes. Due to heat exchange between hot water in the coil and cold water in the boiler, the liquid inside the boiler is heated. This creates a preliminary stock of hot water for human needs.

The entire DHW system has a closed cycle of operation. If hot water is not used for a long time, it starts to cool down. When a person wants to use hot water, he will probably face the problem of an initial absence. When the crane is turned on, the system is activated and water heating starts. But until the time it warms up to the desired temperature it can take several minutes.

Read also:How to choose a boiler - Expert Advice

To be able to use hot water immediately after opening the crane, a circulating pump is installed in the system, which ensures the recirculation of water along the contour constantly, regardless of whether a person uses hot water, or not.

Uninterrupted water recirculation through the boiler is carried out by installing an additional equipment: expansion tank, reverse and safety valves, bleed air valve.

Thus, the recirculation of hot water through the boiler passes through a circulation pump, a heat exchanger and additional equipment that is installed in a single DHW system. As a result, a person does not have to wait for the water to warm up, passing water for some time.

Piping of the boiler with recirculation

One of the most important and complex processes of installing a hot water supply system is the piping of a boiler with recirculation, but it can be realistically carried out by hand.

One of the most economical and efficient water heaters for home and cottages, experts consider an indirect heating boiler. The source of water heating can be gas, electricity or a heat exchanger. It is the heat exchanger that ensures the economical use of the DHW system with the indirect heating boiler.


The proper functioning of the entire system depends on the correct piping of the boiler. The concept of binding can be defined as a feature of the installation and connection of the DHW system to the source of the water heating.

When installing the boiler and the entire system with recirculation, you need:

  • Set the recirculation point. It is, as a rule, located in the center of the heating tank;
  • The cold water is supplied to the bottom opening of the boiler;
  • The hot water outlet must be installed at the top of the boiler;
  • The coolant pipe is connected from above, and goes down (the water circulation of the heat exchanger will flow along the contour, the inlet of which will be at the top of the boiler, and the outlet - from below).
  • The supply of pipes to the source of energy should be carried out according to the rules for the installation of materials, and connected using adapters. Valves and cranes.

It should be noted that the efficiency of the DHW recirculation system depends on the home heating system. This contributes to an increase in the efficiency of an indirect water heater (boiler) by 35%.

The piping of the boiler is recirculated with a standard set of materials: cranes, PVC pipes, adapters, fittings, pumps. Choose only quality certified products from durable materials. Categorically it is not recommended to use corrugated hoses and material of powder metallurgy.

Read also:Door accordion: from advantages to installation features

Boiler recirculation circuit

Water recirculation in the DHW system is necessary in order to provide any point of the system with hot water without additional spillage. For this purpose, a circuit is installed, along which the water from the boiler passes through the entire system, and then returns to the boiler. Recirculation is carried out using a small pump, which works very quietly. Such a system helps to maintain a stable temperature of hot water anywhere in the house.

Among the common recycling schemes, there are several basic options:

  • Installation of a three-way or servo-valve. Apply this method for wall and floor models of boilers. Two pipes (two circuits) are connected to the boiler. One circuit is for heating, the other for hot water. The water heater in this system acts as the main coolant. When the water temperature drops, a servo or three-way valve is used, which starts to work on heating the water. Heating at this time overlaps. After heating the water to the desired temperature, heating heating resumes;
  • Installation of two circulation pumps in one system. Under this scheme, one of the pumps is designed for recirculating hot water through the heating system, and another - along the boiler circuit. This system initially provides a normal water temperature in the boiler, and then in the heating system. A feature of this circuit is the presence of a thermostat and a mode switch, which allows you to disconnect, if necessary, one of the systems;
  • Application of the hydraulic arrow. Applicable if the house has more than two circuits (heating, hot water, warm floor). This scheme is aimed at heating the water, through which heating of all circuits is carried out. This system has a significant drawback - when analyzing water. The heat carrier can not cope with meeting the needs of all people at the same time.
Read also:Connecting the boiler to the cottage

The choice of the method of heating water and heating, as well as the ways of its recycling through the boiler, should be carried out in accordance with clear calculations of all consumers and the capacity of the coolant. Advantage among the basic schemes have a boiler with three-way or servo-actuated valves.

Video on the organization of hot water recycling

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