Circulator pumps, also called circulation pumps or circulating pumps, move liquid around a closed loop, most commonly in heating and cooling systems. Unlike pumps that lift water to a higher point, a circulating pump only has to overcome the friction in the pipework, making them compact, quiet and energy-efficient.
At TF Pumps we supply circulator pumps from Ebara and Lowara, covering everything from small domestic heating circulators to larger commercial hydronic circulator pumps. Browse our ranges below, or call us on +44 1332 913500 if you need help selecting the right circulator for your system.
A circulator pump is a pump designed to circulate liquid, usually water or a water-glycol mixture, continuously around a closed piping circuit. The most common application is in hydronic heating and cooling systems, where the circulating pump moves heated or chilled water from the heat source (boiler, heat pump or chiller) through radiators, underfloor loops, fan coil units or other emitters, and back again.
Because a circulator pump operates in a closed loop, it does not need to lift fluid against gravity, the water column in the return leg balances the water column in the flow leg. The pump only needs to overcome the frictional resistance of the pipework, fittings, valves and emitters. This is why circulator pumps are much smaller and lower-powered than the open-system pumps used for water supply or transfer.
Most modern circulation pumps are centrifugal pumps in construction, a small impeller spins inside a volute casing, creating flow. What makes a circulator pump distinct is its design for closed-system duty: compact body, low head (typically 2–8 metres), quiet operation, and in most current models, an electronically commutated (EC) permanent-magnet motor with variable speed control.
Variable-speed circulator pumps automatically adjust their speed to match the system’s demand. When thermostatic radiator valves close down in rooms that have reached temperature, the pump reduces speed to match the lower flow requirement. This cuts electrical consumption dramatically, modern EC circulators use a fraction of the energy of older fixed-speed models, and the payback period on replacement is often measured in months rather than years.
Wet-rotor circulators: the most common type for domestic and light commercial heating. The rotor runs inside the pumped liquid, which also cools and lubricates the motor bearings. No mechanical seal is needed, so wet-rotor circulators are virtually maintenance-free and extremely quiet. The Ebara Ego and Lowara Ecocirc ranges we supply are both wet-rotor designs.
Dry-rotor circulators: used on larger commercial and industrial systems where higher flows and heads are needed. The motor is separated from the liquid by a mechanical seal. More powerful, but requires occasional seal maintenance.
Solar circulators: designed specifically for solar thermal circuits. They handle higher temperatures and glycol mixtures, with materials rated for the demands of solar thermal duty. The Lowara Ecocirc D5 Solar is purpose-built for this application.
Hydronic circulator pumps for commercial systems: larger variable-speed circulating pumps specified for commercial heating, chilled water and condenser water circuits. Typically flange-mounted (DN40 and above) with higher flow rates and more sophisticated control interfaces for integration with building management systems.
A circulator pump is sized by two numbers: the flow rate the system needs (determined by the heat load and the design temperature difference across the system) and the head the pump must overcome (the total frictional resistance of the circuit at that flow rate, sometimes called the index run). The pump’s duty point must sit on or near the best-efficiency point of its performance curve.
Oversizing a circulator is a common mistake: it causes flow noise, wastes energy and can upset system balancing. Modern variable-speed circulators are more forgiving because they modulate down, but getting the base selection right still matters. We supply circulation pumps from Ebara and Lowara, both offer high-efficiency, ErP-compliant, variable-speed models. Call us on +44 1332 913500 with your system details, and we’ll help you select the right circulator.
If your questions have not been answered here, get in touch with our team for more information.
A circulator pump moves liquid around a closed piping loop, most commonly hot water in a heating system. Unlike open-system pumps, it only needs to overcome friction in the pipework, not lift water to a higher point, so circulator pumps are compact, quiet and low-powered. They are the standard pump type in virtually every domestic and commercial heating system.
A circulator pump is designed for closed-loop duty where it only overcomes pipe friction. A standard centrifugal or transfer pump is designed for open systems where it must also lift liquid against gravity. Circulators are smaller, quieter and use less energy because the head requirement is much lower. If you need to move water from one place to another (tank filling, supply, transfer), you need a centrifugal pump; if you need to circulate water around a loop (heating, cooling), you need a circulator.
A modern wet-rotor circulating pump typically lasts 10–15 years. Older fixed-speed models often last longer mechanically but consume far more energy over their lifetime. Replacing an old circulator with a modern variable-speed model usually pays for itself in energy savings within one to three years.
Sizing depends on the flow rate your system requires (determined by the heat load and design temperature difference) and the frictional head loss of the pipework circuit. A typical domestic heating system needs a circulator delivering around 0.5–1.5 m³/hr at 3–5 metres head. Oversizing is a common mistake, it causes flow noise and wastes energy. Send us your system details and we’ll help you select correctly.
Yes, modern variable-speed circulation pumps are designed as direct replacements for older fixed-speed models. They fit standard connection sizes, use significantly less energy, run more quietly and adapt their speed automatically to the system’s demand. Both the Ebara Ego and Lowara Ecocirc ranges we supply are drop-in replacements for most common installations.
A hydronic circulator pump is a circulating pump used specifically in hydronic (water-based) heating or cooling systems. It circulates heated or chilled water through radiators, underfloor loops, fan coils or other emitters and back to the heat source. The term “hydronic” simply distinguishes water-based systems from air-based HVAC. In practice, most circulator pumps are hydronic circulator pumps.
