Pumps

Circulator pumps for heating, cooling and hot water systems: Grundfos and Wilo

Circulator pumps are an essential component of heating, cooling and hot water systems, ensuring efficient movement of the heat transfer medium in buildings. In the Amegata range you will find products from time-tested manufacturers - Grundfos (ALPHA1L, MAGNA1, UPS series) and Wilo (STAR-Z, Yonos) - for both closed heating systems and domestic hot water (DHW) circulation. By choosing the right pump and matching it with modern HVAC automation, long-lasting, quiet and economical operation of the whole engineering system is ensured.

Pump types

• Wet-rotor pumps: The motor and rotor are immersed in the pumped liquid, which at the same time cools the system and lubricates the bearings. For this reason they run extremely quietly and are well suited to domestic or smaller commercial systems.
• Dry-rotor pumps: The motor is separated from the pumped liquid and cooled by an external fan. These pumps stand out for their high power, so they are most often used in industrial or large commercial building sites.
• Electronic (variable-speed) pumps: Integrated frequency converters and smart controllers automatically adjust the pump speed to the actual system demand, drastically reducing electricity consumption and ensuring the top EEI class A efficiency (Grundfos ALPHA1L, MAGNA1).
• Domestic hot water (DHW) circulation pumps: Pumps with a stainless steel or bronze body (Grundfos UPS N, Wilo STAR-Z), adapted to drinking water systems with constant oxygen ingress.

How to choose the right pump

• Working flow (Q, m³/h) and head (H, m): Calculate the required system flow rate and head, taking into account hydraulic resistance and the building characteristics.
• Connection diameter (DN): Threaded connections are most often used in domestic systems, and flanged ones in industrial systems.
• System type and medium: Assess whether the pump will be used for heating, cooling or preparing domestic hot water - this determines the choice of body material (cast iron, stainless steel or bronze).
• Energy efficiency index (EEI): Choose pumps with EEI ≤ 0.23 to meet modern ErP requirements.
• Nominal pressure (PN): Make sure the selected unit will withstand the maximum working pressure of your system (PN6, PN10 or PN16).

Grundfos pump prices depend on the series, power and body material. Contact us - we will do the calculations for your project.

Pump maintenance and causes of failure

Even top-quality equipment requires regular maintenance. You will find more specific tips on the most popular technologies on the Grundfos website. The main causes of failure:

• Cavitation: Because of too low inlet pressure, vapour bubbles form in the pump; when they collapse they damage the impeller and cause strong noise and vibration.
• Bearing wear and contamination: Solid particles in the system wear down mechanical parts, so dirt separators must be used. Dirt and poor water quality are among the main reasons why heat exchangers fail too.
• Operation outside the curve: If the pump is selected incorrectly and constantly runs away from its optimal duty point, the motor overheats and its service life is shortened.
• Air locks in the system: Air in the system blocks liquid circulation and causes bearing overheating in wet-rotor pumps.

FAQ about pumps

What is the heating medium and how does it affect the pump?
The heating medium is the special heat transfer fluid (chemically treated water or a glycol mixture) circulating in the system. Its proper quality protects the pump impeller and bearings from corrosion and scale build-up.

How do heating and domestic hot water (DHW) pumps differ?
Domestic hot water circulation pumps (Grundfos UPS N, Wilo STAR-Z) are made of stainless steel, brass or bronze so as to be corrosion-resistant and meet hygiene standards for drinking water. Closed heating system pump bodies, on the other hand, are most often cast from cast iron.

Can an old pump be replaced with a new one without changing the pipework?
Yes. New pumps are made keeping standard installation lengths (e.g. 130 mm or 180 mm for domestic systems). Replacing a pump is done quickly and without additional pipework alterations.

Not sure which unit would best meet the requirements of your heating or cooling system? Contact the Amegata specialists - we will carry out precise hydraulic calculations and propose the optimal solution.