Circulation pump: function and savings

Circulation pump: function and savings

In addition to the circulation pump, the circulation pump is one of the most important components of a heating system. The component transports warm water from the boiler to the individual radiators. Then it returns the cooled water back so that it can reheat the heater again. This creates a cycle that generates heat in buildings. Much of today's pumps are old, oversized and thus consume a lot of power. In addition to their old design, they often work around the clock, making them real power wasters. In contrast, modern high-efficiency pumps require only a fraction of the energy. You start only when they are needed.

Task & Function

central heating systems consist of various elements, particularly important is

  • heating burners,
  • heating boilers
  • pressure equalizing container and
  • the heating pump

Using fossil fuels, water in the heating burner is heated and then collected in the boiler. From there, the heating pump conveys the water to the radiators and thus ensures a repetitive heating circuit. The pump can be compared to the human heart and thus has probably the most important task of a heating system. In Heizvorlauf the circulation pump transports the heated water to the radiators, in return the cooled water flows back to the heating burner.


Before electric energy in the households of the world was available, had hot water heating systems according to the gravity principle. In Germany, the system was used until the 1960s, in the former GDR even to the 1980s in new buildings used. Only with the development of the circulating pumps could complex heating circuits with thin tubes be realized.


Original heating systems worked according to the gravity principle . These were replaced by electrically operated circulating pumps, which treat and distribute warm water as needed. Heating systems can thus be much more efficient and energy-efficient. The control of the circulation pump is done in two ways:

  • Manual . The power of the circulation pump can be adjusted manually directly to their
  • Automatic : Modern heating systems have controlled pumps with differential pressure

In order to achieve a constant differential pressure, expressed in meters of water column (mWS), the heating pump must determine the pressure difference between suction and pressure range . The water column is the flow resistance at a certain flow rate. Accordingly, the unit describes the pressure that is needed to overcome this resistance.

Unregulated circulation pumps about 2.5 million circulation pumps in German households were

estimates the energy agency NRW According oversized in 2006. These unregulated heating pumps are still the norm in most households. They work independently of the heat requirement and always with full power. The maximum power of the circulation pump is only required if all the rooms to be heated in a house on the maximum possible room temperature.

Controlled circulation pumps

Unregulated pumps are known to be energy hogs and also for many years no longer installed. Yet they are still used in most households. Their alternative, the regulated pumps, automatically adapt to the current heating water requirement and thus save electricity. In addition, this model operates quietly and consumes 40 percent less than an unregulated circulating pump. Thanks to the energy-saving operation, the cost of replacing the pump will pay for itself within two years.

As mentioned above, regulated standard pumps automatically adapt to the pressure conditions in the heating circuit. In old models, the pressure in the heating network increases with decreasing heat absorption, without at the same time the power and power consumption decreases. The built-up pressure must eliminate overflow valves, so that it does not come to problems. Regulated circulation pumps, on the other hand, register the pressure and automatically reduce the power - pressure and flow are kept almost constant.

High-efficiency pumps

They can also regulate the pressure, but they also have additional functions. The sophisticated technology with permanent magnet motors ensures a particularly low power consumption - about 50 percent lower than with regulated standard pumps. The purchase price is correspondingly higher, but it pays off for new buildings, as there is enough time to recoup the investment.

Solar circulation pump

As the name suggests, it is the task of a solar circulation pump that warms solar collectors Heat transfer fluid to the heat exchanger in the storage tank. Subsequently, the circulation pump transports the liquid back to the solar collector, where it is reprocessed. The solar control controls the pump by sending it pulses, how much liquid it has to circulate.

The energy consumption of such a circulation pump plays an important role in the yield and efficiency of a solar system. Depending on the type of pump, it can consume up to 15 percent of the solar energy. The following will degrade the performance of a solar pump:

  • Hydraulic Throttling
  • Incorrect Sizing
  • Suboptimal Operating Range
  • Asynchronous High Energy Consumption

Subsidy Programs

The Hessian State Government is asking its citizens to provide their heating -Umwälzpumpe to replace a modern, energy-efficient model. Beginning with 07.09.2012, interested parties can benefit from the promotion until 31.12.2013 and collect 100 euros per pump. The action is only valid until the subsidies have been exhausted. The installation must be carried out by a specialist company. The replacement of a pump for one- and two-family houses costs about 500 euros. Included in the price, which will amotize within a few years, are the costs for the pump, complete assembly and commissioning.

Artikelbild: © plumdesign / Shutterstock

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