Comparison Nowa LCA 25-4-180C 4 m

180 mm

vs Gross WRS 25/4-180 4 m

1"

180 mm

— Centrifugal. As the name suggests, this type of pump uses centrifugal force. Their main element is the impeller installed in a round casing; the inlet is located on the axis of rotation of this wheel. During operation, due to the centrifugal force that occurs during the rotation of the wheel, the liquid is thrown from the centre to its edges and then enters the outlet pipe directed tangentially to the circle of rotation of the wheel. Centrifugal pumps are quite simple in design and inexpensive, while they are reliable and economical (due to high efficiency), and the fluid flow is continuous. At the same time, the performance of such units can drop with high resistance in the circuit.

— Vortex. Vortex pumps are somewhat similar to centrifugal pumps: they also have a round casing and an impeller with blades. However, in such units, the inlet and outlet pipes of the working chamber are directed tangentially to the wheel, and the blades differ in design. The method of operation is also fundamentally different — it uses the vortices formed on the wheel blades. Vortex units are significantly superior to centrifugal units in terms of pressure, but they are sensitive to contamination — even small particles entering the impeller can cause damage, significantly reducing efficiency. And the efficiency of vortex pumps is low — 2-3 times lower than that of centrifugal pumps.

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 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 highest liquid temperature that the pump is capable of operating normally.

The possibility of using the unit directly depends on this parameter (see "Suitable for"): for example, models for heating systems must tolerate a temperature of at least 95 °C, and for DHW supply — at least 65 °C. Well, anyway, this parameter should not be exceeded: an overheated pump will fail very quickly, and the consequences of this can be very unpleasant.

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.

The size of the inlet provided in the design of the pump. For plumbing threads (see Connection), the size is traditionally indicated in inches and fractions of an inch (for example, 1" or 3/4"), for flanges, the nominal diameter (DN) of the bore in millimetres is used — for example, DN65.

This parameter must match the dimensions of the mount on the pipe to which the pump is planned to be connected — otherwise, you will have to use adapters, which is not very convenient, and sometimes not recommended at all.

The size of the outlet provided in the design of the pump. The value of this parameter is completely similar to the size of the inlet (see above).

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 heat resistance class of the insulating materials used in the construction of the pump. The higher the heat resistance — the more reliable the device, the less likely it is to ignite or break the insulation in case of overload or overheating. In addition, powerful performant units can become very hot even in normal operations.

In modern pumps, mainly the following classes of insulation are found:

— B. Materials with a heating limit of 130 °C. They are the most modest option by the standards of pumps. Use binding and impregnating compositions of organic origin.

— F. For this class, the heating limit is 155 °C — the average for pumps. Such insulation uses mainly synthetic binders.

— H. Insulating materials based on organosilicon binders/impregnators. Due to this, their heat resistance reaches 180 °C.