Comparison Rudes 15WBX-15 15 m

3/4"

vs Nasosy plus 15WBX-12 12 m

100 mm

The type of rotor the pump is equipped with.

— Wet. "Wet refers to rotors that are in direct contact with the pumped liquid. It achieves several advantages. The liquid provides lubrication and cooling of the rotor — which increases reliability, allowing the pump to work for a long time without additional maintenance, and reduces the noise level. The latter is especially important for residential premises, which is why they use wet rotor pumps. In addition, the units themselves are simple (in design and repair), compact and inexpensive. Their main disadvantage is a lower efficiency than in "dry" models — usually up to 50%. It is not critical for domestic use, but wet rotors are poorly suited for high-performance professional models.

— Dry. The name of such a rotor is because it does not come into contact with the pumped liquid. The key advantage of this design over the "wet" one is high efficiency — about 80%. On the other hand, dry rotors produce more noise and are not suitable for residential applications. Therefore, this option is typical mainly for high-performance units designed for industrial use.

The maximum flow of a pump is the amount of liquid it can pump in a certain amount of time.

Features of choosing the optimal performance option depend primarily on the purpose of the pump (see above). For example, for DHW recirculation models, the pump performance should not exceed the performance of the water heater. If the water heater is capable of delivering 10 litres per minute to the DHW circuit, then the maximum pump performance will be 10*60=600 L/h. The basic formula for calculating the performance of a heating system takes into account the power of the heater and the temperature difference at the inlet and outlet, and for the cold water system — the number of points of water intake. More detailed information about the calculations for each application can be found in special sources, and it is better to entrust the calculations themselves to professionals.

The head can be described as the maximum height to which a pump can lift liquid through a vertical pipe without bending or branching. This parameter is directly related to the pressure that the pump produces: 10 m of head approximately corresponds to a pressure of 1 bar (do not confuse this parameter with operating pressure — see more about it below).

The head is one of the key specs for most circulation pumps. Traditionally, it is calculated based on the difference in height between the location of the pump and the highest point of the system; however, this principle is relevant only for units that boost the pressure of cold water(see "Suitable for"). Circulation pumps for heating and DHW work with closed circuits, and the optimal pressure depends on the total hydraulic resistance of the system. Detailed calculation formulas for the first and second cases can be found in special sources.

The lowest pressure in the circuit where the pump is connected, at which it can perform the main task (see "Suitable for"), providing the claimed operating parameters. The technical features of many modern models are such that some of them can operate at almost zero pressure, simply by the presence of water in the pipe; therefore, this parameter may not be specified at all.

The highest pressure in the circuit at which the pump will be able to work normally.

Of course, this parameter cannot be exceeded — the unit may fail due to a breakdown caused by too high pressure (and even if this did not happen right away, it can happen at any time). However, it is worth choosing a model with some margin — so that the pump can normally withstand pressure surges, which are almost inevitable in any pipe.

The electrical power consumed by the pump during normal operation and maximum performance.

This indicator directly depends on performance — after all, for pumping large volumes of water, an appropriate amount of energy is needed. And the power depends on two main parameters — electricity consumption and the load on the power grid, which determines the connection rules. For example, pumps with a power of more than 5 kW cannot be connected to ordinary household sockets; more detailed rules can be found in special sources.

It is the material from which the motor shaft in the pump is made.

— Cermet. It is a material that combines metals and their alloys with non-metallic components. In modern pumps, different types of cermets can be used, differing in price and quality; usually, the features in each case directly depend on the price category of the unit. However, it is well suited for household models with relatively low performance but is poorly suitable for professional use. Therefore, in pumps of more than 15,000 litres per hour, cermet shafts are rarely used.

— Stainless steel. This material is highly durable and reliable, due to which it is found in almost all categories of pumps — from relatively simple to professional, the performance of which is in the tens of thousands of litres per hour. However, it is somewhat more expensive than cermets.

In this case, the country of origin refers to the country from which the product brand originates. A brand, in turn, is a general designation by which the products of a particular company are known in the market. The country of its origin does not always coincide with the actual place of production of the product: to reduce the cost of production, many modern companies transfer it to other countries. It is quite normal for products, for example, of an American or German brand, to be made in Taiwan or Turkey. Contrary to popular belief, this in itself does not lead to a decrease in the quality of the goods — it all depends on how carefully the brand owner controls the production. And many companies, especially large and famous ones, monitor the quality very zealously — after all, their reputation depends on it.

The installation length is the distance between the inlet and outlet of the pump, in other words, the length of the segment occupied by the pump in the circuit. This parameter allows you to estimate the amount of space required for the unit, and determine the length of the pipe section that needs to be cut.