Hot Water

Hot water supply is the provision of the population, including its domestic needs, as well as production needs, with high-temperature water (up to +75 degrees Celsius). It is an important indicator of the level and quality of life, as well as a condition for compliance with sanitary and hygienic standards. The hot water supply system consists of special equipment, functioning in combination, which serves to heat water to the desired temperature, as well as to supply it to water intake points.

Most often, this system consists of the following elements:

  • water heater;
  • pump;
  • pipes;
  • fittings for water supply.

Hot water requirements  


Frequently scheduled shutdowns and low-temperature conditions are the main disadvantages of the central hot water supply. Such situations occur frequently, but according to current laws, their frequency is strictly regulated. 

  1. The water temperature should not be lower than +40 ° С, and its deviation should not exceed 3-5 ° С.
  2. Total DHW shutdown time. What is it and what indicators should be observed? The total time is no more than 8 hours a month.
  3. The maximum period of maintenance work in the summer season is 14 days.

To control the flow rate of the coolant, special devices for hot water supply are installed. Meters are installed only by representatives of the management organization with which an agreement is concluded for the supply of hot water to an apartment or house.

Device types  

The hot water supply system can be of two types.

  • An open system has a coolant.  Water is supplied from a central heating system. It is so named because the supply comes from the heating system. This system is usually used in apartment buildings. For private homes, an open system would be too costly.
  • A closed system functions differently and has its own differences. First, cold drinking water is taken from a central water supply system or an external network, then it is heated in a heat exchanger and only then is it supplied to the water intake points. This water can be used for cooking, as it does not contain elements harmful to health.

There is also an independent hot water supply system. Water is heated in a boiler room or heating point, then supplied to the house. It is called independent because it operates separately and is not connected to the heating system. It is used in private homes or cottages.

As for water heaters, they are divided into two types.

Their choice depends only on the wishes of the owner, as well as on the living conditions of the premises.

  • Flowing. They do not accumulate water, but heat it up as needed. Such a heater is activated instantly as soon as the water is turned on. They can be electric or gas.
  • Accumulative. Such hot water boilers collect water in a special tank and heat it up. Hot water can be used at any time. Electric boilers are large in size.

Circulating way

According to this method, hot water is constantly circulating through a closed-loop system: a heating station – a central system – a substation – a water supply system – and returns back. This is due to several reasons:

  • a large number of consumers;
  • cooling water when the system is idle;
  • other possible reasons.

Practice shows that this method makes it possible to quickly obtain hot water from a kitchen faucet. It is always hot and ready for use. When the system stops, the water will cool down, which will lead to large heat losses. In multi-storey buildings, this is done by branching the riser to additional pumps or blocks.

With this method, some difficulties are possible: everyone knows the problem that heated towel rails in the bathroom are heated in the summer, and there is no way to reduce their temperature. Hot water is constantly in them at any time. You can make a heating correction by installing a control valve and adding a pipe through which water will flow when the valve is closed.

Dead end way


With this method, the DHW system operates with less efficiency, since the consumer is equipped with a final dead-end plumbing system. It contains only supply pipes that are not equipped with a return circuit. Hot water comes in when the mixer is opened. When it is closed, the water in the pipes stops and cools slowly.

In practice, it looks like when the tap is inactive for a long time, for example, at night, cold water will first come in, and after a while, hot water. The dead-end supply method is most often used in their own homes, which are connected to the water supply. Today, it is the dead-end method that has become the most common due to the popularity of individual electric boiler heaters.

Central and autonomous hot water supply

Each of the species has its own advantages and negative factors. The central system is more convenient for the consumer if its operation is constant and meets the standards for temperature and water quality. But such conditions are not always observed in our country and are more like an exception than natural conditions.

The central system does not always provide reliable comfort in the dwelling and is often a “headache” for residents. To a greater extent, it depends on the diligence of local bosses, supervisory and regulatory bodies.

The autonomous method is costly since it is necessary to install special structures, laying water pipes. But its performance and degree of comfort are significantly higher than the central system. The consumer can independently set the temperature level and control the consumption of the coolant.

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