Circulation pumps are an essential element of many technical systems, including heating, ventilation and air-conditioning installations. What should you know before purchasing one?
The efficiency of the heating system depends on many factors. Of course, the most important factors are the quality of individual elements and their technical condition, as well as the selection of appropriate solutions for the specificity of a given installation. Sometimes, however, even meeting these requirements does not guarantee effective heating operation. Fortunately, such problems can be solved relatively easily.
In many cases, the appropriate solution is to install a circulation pump , i.e. a device that stimulates the circulation of the working medium. Pumps of this type are usually used in central heating installations, but their use is not limited to this technology. In the new entry, we discuss their functionality and principle of operation and explain how to choose the model best suited to our needs.
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Selecting the appropriate size of circulation pump
As we mentioned a moment ago, the circulation pump may be an element of a central heating or other system. They are also used in underfloor heating or solar installations. Thanks to this solution, it is also possible to deliver water from the heater to consumption points in installations not connected to public water supply infrastructure.
The correct selection of a circulation pump requires taking into account various factors. One of them is the size of the device. There are five types of circulation pumps on the market - with installation lengths of 80, 130, 150, 180 and 220 millimeters. This parameter is especially important when replacing an old pump with a new one or when it is to be located in a small box. Due to the specificity of a given location, it is often impossible to install a larger device.
Check circulation pumps at the Onninen wholesaler
When buying a circulation pump, you should also pay attention to its quality. At the Onninen wholesaler, we offer a wide selection of circulation pumps from the best manufacturers - e.g. FERRO circulation pump (model 25-60-180 with solid cast iron body and aluminum housing), ONNLINE circulation pump (model EQC-M 25-6/180 with electronically commutated synchronous motor) or GRUNDFOS circulation pump (model ALPHA2 25-40 very low power consumption with radio communication function).
Characteristics of constant differential pressure and the type of circulation pump
Another issue to remember when choosing a circulation pump is its type - and specifically its operating characteristics. In this respect, we distinguish three types:
pumps with constant differential pressure characteristics;
pumps with proportional characteristics;
constant pumps.
The former are used where it is necessary to maintain a constant pressure difference between levels, and therefore a constant lifting height. This parameter should be maintained regardless of the amount of working medium in the installation. Achieving this effect requires automatic adjustment of the pressure and power of the device. The diagram of pumps with constant differential pressure characteristics consists of straight sections that break at the end of the field.
Circulation pump with proportional characteristic
The next type are pumps with proportional characteristics. Their operation consists in increasing the lifting efficiency with increasing the flow of the working medium. The use of pumps with this characteristic mainly covers installations in which different flow resistances occur in individual sections. The capacity increases until the lift height reaches its maximum, and then it begins to decrease very much.
This situation occurs, for example, in central heating systems with thermostatic heads. Due to the different distances between individual receivers (radiators) and the heat source (boiler), the pump must proportionally adjust the operating parameters in each part depending on the opening or closing of the heads. The operation graph of proportional pumps shows steep curves, rising to a maximum and then falling.
Circulation pump with constant characteristic curve
The constant characteristic curve was used primarily in older models of circulation pumps. Devices of this type raise the working medium to a height corresponding to the set gear. Changes to the installation do not affect this operating parameter. The use of this type of pumps is limited primarily to installations that do not have regulating elements and require constant flow. The graph shows rounded curves.
The selection of a circulation pump should be consulted with a specialist. If you have any doubts as to which type and model will work best in a given installation, please contact us - our employees will provide the necessary support and help in choosing the right product.