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Circulation pumps are installed in heating systems with forced or natural circulation. It is needed to increase heat transfer and to be able to adjust the temperature in the room. Installing a circulation pump is not the most difficult task; if you have a minimum of skills, you can do it yourself, with your own hands.
What is a circulation pump and why is it needed
A circulation pump is a device that changes the speed of movement of a liquid medium without changing the pressure. In heating systems, it is placed for more efficient heating. In systems with forced circulation, it is an indispensable element, in gravitational systems it can be set if it is necessary to increase the thermal power. Installing a circulation pump with several speeds makes it possible to change the amount of heat transferred depending on the temperature outside, thus maintaining a stable temperature in the room.
There are two types of such units – with a dry and wet rotor. Devices with a dry rotor have a high efficiency (about 80%), but they are very noisy and require regular maintenance. Wet rotor units operate almost silently, with normal coolant quality, they can pump water without failures for more than 10 years. They have a lower efficiency (about 50%), but their characteristics are more than enough to heat any private house.
Read about the choice of a circulation pump for heating systems here.
Where to put
It is recommended to install a circulation pump after the boiler, before the first branch, but on the supply or return pipeline it does not matter. Modern units are made from materials that normally tolerate temperatures up to 100-115 ° C. There are few heating systems that work with a hotter coolant, therefore considerations of a more “comfortable” temperature are untenable, but if you are so calmer, put it in the return line.
There is no difference in hydraulics – the boiler, and the rest of the system, it does not matter whether there is a pump in the supply or return branch. What matters is the correct installation, in the sense of tying, and the correct orientation of the rotor in space. Nothing else matters.
There is one important point at the installation site. If there are two separate branches in the heating system – on the right and left wings of the house or on the first and second floors – it makes sense to put a separate unit on each, and not one common one – directly after the boiler. Moreover, the same rule is preserved on these branches: immediately after the boiler, before the first branching in this heating circuit. This will make it possible to set the required thermal regime in each of the parts of the house independently of the other, and also in two-story houses to save on heating. How? Due to the fact that the second floor is usually much warmer than the first floor and much less heat is required there. If there are two pumps in the branch that goes up, the speed of the coolant is set much less, and this allows you to burn less fuel, and without compromising the comfort of living.
Harness
There are two types of heating systems – with forced and natural circulation. Systems with forced circulation cannot work without a pump, with natural circulation they work, but in this mode they have a lower heat transfer. However, less heat is still much better than no heat at all, so in areas where electricity is often cut off, the system is designed as hydraulic (with natural circulation), and then a pump is slammed into it. This gives high efficiency and reliability of heating. It is clear that the installation of a circulation pump in these systems has differences.
forced circulation
Since a forced circulation heating system without a pump is inoperative, it is installed directly into the break in the supply or return pipe (of your choice).
Most problems with the circulation pump arise due to the presence of mechanical impurities (sand, other abrasive particles) in the coolant. They are able to jam the impeller and stop the motor. Therefore, a strainer must be placed in front of the unit.
It is also desirable to install ball valves on both sides. They will make it possible to replace or repair the device without draining the coolant from the system. Turn off the taps, remove the unit. Only that part of the water that was directly in this piece of the system is drained.
natural circulation
The piping of the circulation pump in gravity systems has one significant difference – a bypass is required. This is a jumper that makes the system operational when the pump is not running. One ball shut-off valve is installed on the bypass, which is closed all the time while pumping is in operation. In this mode, the system works as a forced one.
When electricity fails or the unit fails, the faucet on the jumper is opened, the faucet leading to the pump is closed, the system works like a gravitational one.
Mounting Features
There is one important point, without which the installation of the circulation pump will require alteration: it is required to turn the rotor so that it is directed horizontally. The second point is the direction of the flow. There is an arrow on the body indicating in which direction the coolant should flow. So turn the unit around so that the direction of movement of the coolant is “in the direction of the arrow”.
The pump itself can be installed both horizontally and vertically, only when choosing a model, see that it can work in both positions. And one more thing: with a vertical arrangement, the power (created pressure) drops by about 30%. This must be taken into account when choosing a model.
Power connection
Circulation pumps operate from a 220 V network. The connection is standard, a separate power line with a circuit breaker is desirable. Three wires are required for connection – phase, zero and ground.
The connection to the network itself can be organized using a three-pin socket and plug. This connection method is used if the pump comes with a connected power cable. It can also be connected via a terminal block or directly with a cable to the terminals.
The terminals are located under a plastic cover. We remove it by unscrewing a few bolts, we find three connectors. They are usually signed (pictograms are applied N – neutral wire, L – phase, and “earth” has an international designation), it is difficult to make a mistake.
Since the entire system depends on the performance of the circulation pump, it makes sense to make a backup power supply – put a stabilizer with connected batteries. With such a power supply system, everything will work for several days, since the pump itself and the boiler automation “pull” electricity to a maximum of 250-300 watts. But when organizing, you need to calculate everything and select the capacity of the batteries. The disadvantage of such a system is the need to ensure that the batteries are not discharged.