Indirect heating boiler - what is it?
Indirect heating boilers differ from all other sources of warm water in that this design does not have its own heating element. Water heating in such a system is carried out due to the influence of external heating devices. This can be a boiler, central heating or solar panels.
The principle of operation of the indirect heating boiler
A distinctive feature of the principle of operation of an indirect heating boiler is that this device works only in conjunction with external heating sources. From this source, the coolant is supplied through a coil located inside the boiler. Thanks to the operation of the pump, the coolant circulates and thereby heats the located in the boiler water. The entire system is covered with thermal insulation materials (expanded polystyrene or polyurethane) to reduce heat loss.
Cold water enters the boiler tank through the water supply pipes. Special branch pipes are used to connect to the heat carrier supply source. Having passed the entire cycle along the coil, the heat source returns to the heating system through the outlet pipe. When choosing a boiler, one should be guided by the power of the heating source, if this value is insufficient, the water will not have time to heat up to the desired temperature.
Water connection
For an uninterrupted supply of warm water, the rules for connecting an indirect heating boiler should be strictly observed. The main nuance of the connection is that cold water must be supplied from below, i.e. the inlet pipe is connected at the bottom of the boiler. However, there are boilers where the inlet to the cold water supply is at the top - this means that the water goes through the entire system to the lowest point.
As for the hot water outlet, it is usually located at the top. The nozzle takes in the upper layers of water, which are always the hottest in the tank. Thanks to such a system, hot water will be supplied until there is not a single gram of warm water in the tank, only after that cold water will flow.
Connection diagram
The piping of the indirect heating boiler can be done with your own hands, but for this you need to know some of the connection features. The coil, along which the coolant moves from the source, is a spiral pipe running along the entire length of the boiler. Under the influence of the buoyancy force of the pump, the coolant flows along the circuit and in cold water is cooled to a certain temperature. After several cycles, the temperature of the coil is equalized with the temperature of the water inside the boiler, at this moment the relay is activated, opening the electrical circuit in the electric pump.
As soon as the water temperature drops to a certain level, the circuit closes again and the supply of hot coolant to the coil is resumed. For greater heating efficiency and reducing energy costs, the coil must be connected from above to the heat carrier source. Otherwise, the coolant would not be cooled to the maximum value, passing warm layers of water at the end of its path, which would reduce the efficiency. Below is a typical diagram for connecting an indirect heating boiler to a heat source and its connection with hot water consumers.
Advantages of an indirect heating boiler
Among the large number of advantages of indirect heating boilers, many note the absence of energy costs. However, this statement is not entirely true, energy costs are present due to the cooling of the coolant, but they are several times less than when using boilers powered by electricity or other energy sources. In addition, the power of indirect heating boilers is higher than that of many analogues, which means that the water can heat up much faster. This advantage allows the boiler to be connected to several hot water consumers, for example, a mixer in the bathroom and in the kitchen at the same time.
The main advantages of the indirect heating boiler:
- Reducing energy consumption;
- Large production capacity;
- Heating speed;
- Easy to connect;
The disadvantages of this type of boilers include the fact that they depend on the connected heat sources. For example, if the heating system acts in this capacity, then it will not work in the summer.
In this case, you have to use electricity, for this, almost all models of boilers are equipped with electric heating elements.
Indirect heating boilers are slightly more expensive than electric counterparts of the same volume. Another disadvantage can be considered the energy consumption for heating the room for heating water. In private homes, this problem is solved by increasing the fuel supply. In any case, as a result, energy losses will be lower than when using alternative methods of producing hot water.
Analyzing the numerous reviews of the owners of indirect heating boilers, we can come to the conclusion that this system is widely in demand. Despite the fact that many are faced with the problem of warm water supply in the summer season, this problem is still solvable.
Even if the design of the boiler does not provide for heating from electricity, do not despair. In order not to waste a large amount of fuel for the operation of the heating system, it can be switched to economy mode. To do this, it is only necessary to shut off all heating circuits, with the exception of what is supplied to the boiler.