Many modern solutions of water heating houses require the use of a circulation pump. Design and installation of heating systems with circulation pump should be implemented taking into account the technical issues that arise due to the rapid movement of the coolant.
High pressure in the heating circuit allows to realize a plurality of wiring schemes.
The content of the article:
- Technical features of the basic system components
- General requirements for the pumping group
- Subtleties choice boilers and furnaces
- Assembling and testing water loop
- Embodiments heating under forced circulation
- Application of the upper and lower wirings
- Varieties of one pipe connection schemes
- Methods of Using the double-tube embodiment
- Use of distribution manifold heating
- Heating via underfloor heating
- Useful videos on the topic
Technical features of the basic system components
Forced scheme differs from the natural addition of one or more circulators.
Due to increased pressure and coolant flow rate, and rules for the arrangement of nodes circuit elements changing. This fact should be taken into account to provide a quality heating system with forced circulation.
General requirements for the pumping group
Circulating pumps are selected based on the requirements in terms of distilled water (cubic meter per hour) and the pressure (meter). Calculation of both parameters depends on the cubic capacity of the heated housing and heating method, as well as the length of the water circuit and its diameter pipes. The pump should be chosen to be the parameters were not "butt" to the system requirements. This will add, if necessary, elements of the contour without replacing the pump.
Basically pumps rated at 220 volts, but there are also supporting 12 volts. When surges necessary to put the stabilizer in order to prevent failure of the device. In the event of frequent power outages need to take care of the presence of an uninterruptible power supply. There is no need to take powerful UPS - for heating of private homes are rarely used devices with consumption of more than 150 watts per hour.
Conventionally, the circulation pumps can be divided into two types of motor position. Devices with dry rotor have a higher efficiency, but have a high noise level and reduced resource than glandless.
If the wiring system allows for natural movement of the coolant circuit, the pump should be installed through the "bypass". In this case, when a malfunction or a power outage may switch to the heating mode gravitational circulation. Through the broken water pump can also be moved, but it will create a strong resistance to its motion.
Particularly urgent is the problem stop the pump when using the fireplace or furnace heating. In this case, the furnace will continue and possibly heat exchanger boiling water therein and permanently exit the entire system out of operation.
Pump installation to perform better on the return pipe, because a lower water temperature will extend its life. If it is not possible to install the pump in a different location other than on the tube coming out of the boiler, it is necessary to use a pump with ceramic seals. Although they can withstand temperatures up to 110 degrees Celsius, but at boiling system and they can cause problems with the operation.
Subtleties choice boilers and furnaces
Use as a heat generator of electrical and gas boilers, long burning furnaces attractive from the standpoint of ease of control of heat input via heat exchanger. The use of solid fuel furnaces, especially self-made designs, is fraught with inadequate or excessive heat generation. However, their use is often justified from the standpoint of low cost and availability of fuel.
Now available a variety of models of electric and gas boilers with an integrated pump. On the one hand build circulating system fitted to the boiler capacity and allows not engage in buying and installing a separate pump. On the other hand in case of breakage integrated pump, it is not so easy to be repaired or replaced as separate.
Requirements to the boiler by using forced circulation is the same as in the natural:
- The boiler output must meet the heating needs of the house in the most demanding conditions for the area. It is desirable to have a small supply of power (10-20%) because of possible force majeure circumstances that may occur in the heating system.
- It is necessary to ensure the flow rates without boiling in the heat exchanger. This is a requirement when using "oven - pump" combination to perform better than in the gravity model of fluid motion.
To prevent boiling of water in the boiler heat exchanger set enough power adjustment depending on the outlet fluid temperature. This process operates with any type of circulation.
For furnaces with natural circulation is not possible to prevent boiling of coolant in the event of excessive quantities of fuel loaded. The only option available when the pump is an increase in liquid form fed through the heat exchanger. Moreover, such emergency system can be made automatically using a thermostat and a pump speed control unit.
Assembling and testing water loop
When the heating circuit with forced circulation will have higher water velocity than the gravitational model. Therefore, it is possible to use smaller diameter tubes at the same parameters of the building heating. This reduces the cost of the water heating costs in terms of pipes, fittings and valves. In addition, the smaller the diameter of the contour elements easier to hide in a technological niche or write on the interior.
Compared with natural circulation to the hydrostatic fluid column pressure added to increased hydrodynamic flow pressure. Therefore, in order to avoid leakage, or even more, breaking some of the rules you need to adhere to the system.
In the case of transition from the gravity circulation forced to have to liquidate everything, even minor leaks in the circuit. As the pressure increases the flow rate increases, that in addition to the problem in the room will cause a decrease in the amount of coolant and its excessive aeration (air saturation).
Before the onset of the heating period necessary to test hydraulic circuit maximum strength with a usable or even slightly higher pressure. This will allow to identify problems and eliminate them before the onset of cold weather, when the prolonged heating stop for repairs is undesirable.
Since the rate of coolant will be moving more than 0.25 meters per second, according to snip 41-01-2003 no need to maintain a constant bias of pipes to remove air from the circuit. Therefore, when the forced circulation installation pipes and radiators little simpler than the case of gravity circuit.
Embodiments heating under forced circulation
The use of forced circulation allows you to move away from the principle of the design layout with mandatory taking into account the difference in hydrostatic pressure, which is necessary for operation at the gravitational scheme. This adds variability in modeling the geometry of the water loop, and provides the ability to use solutions such as collector heating or floor heating a large area.
Application of the upper and lower wirings
Any heating circuit can be arbitrarily assigned to the upper and lower wiring. When the upper wiring hot water rises above the heating devices, and then flowing down, heat radiators. At the bottom - hot water is supplied from below. Each method has its positive side.
The upper wiring is also used in a natural circulation. Therefore, the heating circuits of this type allow to use both types of circulation. This is, firstly, provides a choice, and, secondly, improves system reliability. In case of power failure or pump failure movement of water along the contour will continue, albeit at a slower rate.
When using the lower wiring total length of the pipes smaller, which reduces the costs of setting up the system. In addition, there is no need to lay the risers on the top floor, which is good from the perspective of interior design. Lower hot water feed pipe paving or basement floor or ground level.
Varieties of one pipe connection schemes
Single-pipe circuit uses the same tube for supplying hot water to the radiators and the heating of cold tap boiler. With such wiring is reduced by almost half the length of the tubes used, reducing the number of fittings and valves. However, heating radiators occur sequentially, however counting the number of sections necessary to consider a gradual decrease in the flow temperature.
Monotube circuit may be implemented in the horizontal and vertical embodiments. If forced circulation, in the case of vertical risers can be carried out hot water supply not only from above but also from below. Feasibility of use of a particular embodiment depends not only from the convenience of the pipes, but the maximum allowable number of radiators in one single pipe riser circuit.
Connect the radiators in two ways:
- Heat transfer fluid successively flows through all the radiators. In this case, the minimum number of pipe, however, if necessary, disable one of the radiators, it is necessary to stop the entire system branch.
- Heat transfer fluid can flow to bypass the radiator according to the defined layering - "Bypass". With the help of crane system can redirect the flow past the radiator that will allow for its repair or removal without interrupting the heating.
Monotube scheme is often used for heating, but in the case of a large number of radiators, another embodiment is used for their uniform heating.
Methods of Using the double-tube embodiment
Scheme heating circuit with a second pipe for discharging the cooled water to the boiler is called the double pipe. Meters tubes increases as the number of connections and devices. However, the main advantage of the system is that each radiator coolant fed the same temperature. Twin-Tube makes it a very attractive option.
When water heating is used with a forced circulation and a horizontal and a vertical wiring. Moreover, in the vertical embodiment may use the upper and lower hot water.
Since the temperature of the water supplied to all radiators identical, then the geometry circuits depends only on the following factors:
- minimizing the amount of footage pipes and connections;
- ease of the heating circuit through walls and ceilings;
- the ability to enter the heating elements in the interior.
Depending on the movement of hot and chilled water circuit is divided into two pipe passing and blind. In passing scheme movement in both pipes in one direction. Cycle coolant circulation has the same length for all parts of the radiators in the system, so the speed of heating of the same.
The deadlock scheme radiators located close to the boiler heat up faster. However, for systems with forced circulation it is not very important because of the high velocity of the water in the circuit. Therefore, when choosing between option associated and guided deadlock condition for the convenience of the return pipe. The vertical wiring patterns at the lower dead-end system is obtained, and at the top - a tail.
Use of distribution manifold heating
Another popular method of heating is now the organization is to create a collector or beam pattern. To some extent, this scheme can be called subspecies of two-pipe, although it is applied in the organization of one-pipe heating circuits.
Only the distribution of the hot coolant and chilled collection does not take place with the main riser, but with the special distribution node devices - reservoirs. Such a system works stably only by using forced circulation.
Dispensing assembly for two-pipe system is a complex combination of feeder and return reservoirs, via which the balanced temperature and pressure feed coolant. Each branch unit feeds one heating element or a small group. The branches are usually located under the floor, each floor of a multistory building is served by one set in the center of the collector.
Despite the obvious advantages of such an option of organization of heating, in the collector system has two significant disadvantages:
- maximum length of the pipelines, so this option is the organization of the water circuit requires substantial financial investments;
- in this embodiment the pipe located generally under the floor or in the walls, so in the case of adding heaters to make any changes will be very difficult.
All collectors are mounted, usually in a special locker, as shut-off valve is located in the same place and it needs to access. Crane co-location is very convenient. If you turn on or turn off radiators requirements or the occurrence of the contingency is sufficient to have access to the closet and there is no need to visit all premises.
The manifolds can be of a simple structure consisting of two combs and minimum valves. Complex nodes can also include automatic thermostats, electronic valves, faucets, automatic air release devices, sensors and control units, a water drain valve, separate circulation pump.
These systems may most accurately adjust the temperature in the house, but requires a good understanding of the foundations and water heating operation nuances.
Heating via underfloor heating
One of the most comfortable way of heating is considered the organization of floor heating. It should be noted that the installation of such an option of heating living rooms, showers, kitchens and other rooms is quite complicated. Radiant floor heating a large area is possible only in the organization of forced circulation, because of the need to create pressure in the system of long narrow tubes.
The pressure necessary to overcome the resistance of narrow pipes with a plurality of bends. Moreover, the pressure to be achieved, allowing to remove air from the floor heating tubes which are arranged horizontally.
There are a large number of tubes laying combinations. For small spaces are used with a single input circuit for hot water and an outlet for cooled. For larger rooms organize more complex system of floor heating with the use of the distribution manifold. Often fragments circuit for underfloor installed separate circulation pumps.
Useful videos on the topic
A detailed exposition of the double pipe and a rather complicated circuit house for heating:
an open system based on coal-fired boiler to testify:
closed-type system for the three-story house on the basis of a gas boiler:
Using the pumps when water heating space greatly facilitates circuit design, making possible options that are not available for the gravity model. Proper selection of equipment will solve the problem of housing the heating, making the process convenient and simple.
