Types of piping for indirect heating boiler + installation and connection rules for this unit
Indirect heating boiler has long been known as one of the best ways to provide a private house or cottage with enough hot water. Quite successfully, these devices are also used in apartments, offices, enterprises, etc. The principle of operation of the boiler is so simple that it is not so difficult to make it yourself. However, the efficiency of this device depends to a large extent on how correctly the indirect heating boiler piping scheme is selected.
Basic principles of connecting a boiler
Water is supplied to the device in two circuits. The first is the heating circuit, which is usually connected to a home heating system. The second circuit is designed for heated water, which comes from the water supply system, and then is discharged into the bathroom, into the kitchen, etc.
Figuring out how to install indirect heating boiler, first things first, remember the following principles:
- Cold water must be supplied to the lower part of the boiler, and hot water is discharged at the top of the device.
- Coolant must flow into the tank from top to bottom, i.e., water or antifreeze is supplied to the upper boiler nozzle and returns to the system from the lower.
- The recirculation point will be located in the center of the boiler tank.
Compliance with these principles will maximize the efficiency of the device, since the water temperature in the upper part of the boiler will remain high enough, and then the coolant will also heat colder water in the lower part of the tank.
Tying options for different situations
Most often, when connecting an indirect heating boiler, three main schemes are used:
- three way valve option
- application of two circulation pumps
- use of a hydraulic arrow.
In addition, it is worth considering the use of a recirculation system, which can significantly improve the quality of hot water in a private house or apartment.
How to use a three-way valve?
When consuming a large amount of hot water, the connection of an indirect heating boiler with the help of a three-way valve is most often used. In this case, it is necessary to create two heating circuits: the main one, which heats the room, and a separate circuit, necessary for heating the water in the boiler. To distribute the flow of coolant between these circuits, a three-way valve is used, which is controlled by a boiler thermostat.
The three-way valve in the piping diagram of the indirect heating boiler is used to control the direction of flow of the coolant. The valve is controlled by a boiler temperature sensor.
This system works as follows. When the water temperature in the tank drops below the set value, the valve directs the coolant to the boiler heating circuit. After the water is heated to the required level, the valve returns the flow of coolant to the main heating circuit.In this case, the main role is played by the heating of water in the boiler tank, and not the heating circuit.
Note! In areas with very hard water, it is recommended to use an indirect heating boiler with a three-way valve instead of a double-circuit boiler, the elements of which fail too quickly under such operating conditions.
For the correct operation of this type of system, it is very important to correctly set the thermostat. The fact is that if the maximum temperature of the water in the tank is higher than the temperature of the heating medium in the boiler, the water in the boiler will be constantly heated. Switching to the heating circuit will not occur, since the maximum temperature in the boiler will not be reached.
Dual pump system
Instead of a three-way valve, a system with two recirculation pumps and a non-return valve can be used. In this case, the installation of the indirect heating boiler also includes two parallel circuits: the heating circuit and the boiler circuit. A separate circulation pump is used to control each circuit.
In the indirect boiler circuit, using two circulation pumps, the heating circuit and the boiler circuit are mounted in parallel, however, the main role is played by the boiler circuit
Since the hot water line has priority, circulation pump the boiler circuit is installed in front of the heating system pump. To control the pumps, the same boiler temperature sensor is used, obeying the signals of which the pumps turn on and off. A dual-pump circuit can be very convenient when using a heating system that includes two boilers. At the same time, one boiler is fully used to heat the room, and the second is connected to both the heating system and the boiler.
When the water cools in the boiler, the coolant flow is sent to heat it, and at the end of the process it returns to the heating system. The non-return valve is necessary so that the coolant flows do not mix.
Do not be afraid that the quality of heating of residential premises will suffer due to the use of a boiler for contour heating. The water in the DHW system heats up very quickly, usually less than an hour. For this short time, the rooms simply do not have time to cool down.
How does the hydraulic needle work?
In modern private houses and even in ordinary apartments, the heating system can be quite complex. In addition to the radiator line, it often includes a boiler heating circuit, a warm floor system, and other elements.
The hydraulic arrow in the circuit of the circulation pump strapping is necessary to regulate the coolant flows and compensate for the pressure difference in individual parts of a complex heating system
Each such circuit is equipped with a separate circulation pump. At the same time, flows in different circuits of the circuit must be balanced. To control such multi-circuit heating systems, a hydraulic distributor is used, which may include a hydraulic needle and a manifold. It is also possible to neutralize pressure drops in individual circuits using special balancing valves.
The more complex the heating system, the more carefully it should be installed. The design of connecting an indirect heating boiler using a hydraulic arrow is best left to an experienced specialist, since it is quite difficult to adjust such a system “by eye”.
A few words about the benefits of recycling
In order not to have to wait until the cold water in the hot water faucet is replaced by heated, use a recirculation system. When it is applied, a looped line is created, along which the ox constantly moves and is constantly heated, that is, it does not have time to cool down.Thus, the consumer receives hot water almost instantly as soon as the corresponding tap is opened.
To create a constant cycle, you need another circulation pump. A very convenient addition to such a system is a heated towel rail.
