Intelligent pumps for hot water circulation in commercial buildings

Designing the optimal system for hot water circulation

Your challenge:

In hot water circulation applications there is a need for instant hot water as soon as the tap is open. The traditional solution is to use a constant speed pump to provide the needed pressure in the hot water and circulation pipeline. Typically, the pump runs at maximum speed and is usually throttled by a valve. This results in high energy consumption and pumps that cannot adapt to changes in the system.

Our solution:

A more efficient solution for hot water recirculation is to use a constant temperature controlled pump. The constant temperature control mode on the TPE3 will always maintain the desired water temperature at the taps and in the circulation pipe. If the temperature increases the pump ramps down and if temperature decreases the pump will increase its performance. This eliminates the need for pump throttling valves and means overflow will never occur, resulting in substantial energy savings.

Viborg Hospital experienced the benefits of the Grundfos TPE3 pumps. Read our paper about the retrofit project here.

Case: Regional Hospital Viborg

The intelligent solution: A temperature controlled pump


Fixed-speed pump

A constant speed pump ensures instant hot water but increases energy consumption

To ensure immediate hot water when needed, a separate circulation pipeline is installed. Traditionally, a constant speed pump is used for the continuous circulation of hot water. Here a constant and unnecessarily high pressure is provided, which is why a pump throttling valve is required. This increases both the investment costs as well as energy consumption.

Temperature controlled pump

A temperature controlled pump ensures performance always matches demand

Instead of throttling the flow from a fixed-speed pump you can install a temperature controlled pump such as the MAGNA3 or TPE3. The pumps’ constant temperature control modes ensure the desired water temperature is always kept. If the water temperature increases, the pump will ramp down and if the temperature decreases, the pump ramps up. Wireless technology and integrated sensors ensure seamless control and a continual match between performance and demand. This allows you to cut down on energy use and save the cost of throttling valves.



  • High efficiency commercial heating and cooling circulators
  • Constant temperature control mode allows the pump to adapt to the actual water temperature
  • Sophisticated control modes, such as FLOWLIMIT and AUTOADAPT, cut energy and installation costs
  • TFT screen and wireless communications ensure easy set-up and diagnostics
  • Logging and BMS communications aid ongoing system optimisation

Commissioning TPE3 in a water recirculation system

Grundfos is proud to introduce its MGE pump motors with the new IE5 status - the world's highest energy efficiency rating. Discover how our ground-breaking Grundfos iSOLUTIONS motors meet the strictest IE5 criteria to deliver you an unsurpassed level of energy efficiency.


Case study: Viborg hospital - Virtually no waiting time for hot water


Facts: Viborg Hospital

TPE3 intelligence made this possible. Steady water supply, constant temperature and very short waiting times were crucial for Viborg Hospital.

Patient capacity: 500 beds

Floor area: 95.000 m2

Employees: 2900

Water consumption in 2014: 967.000 m3



Constant temperature control mode

The constant temperature control mode makes the pump adapt its performance to the system’s need. All pump settings are managed on the pump display or the Grundfos GO app.



  • MGE motors with IE5 status - the world's highest energy efficiency rating
  • The right water temperatures are always guaranteed
  • Temperatures can be read out and documented with the Grundfos GO
  • Design and specification is simpler as everything is based on temperatures
  • No need for pump throttling valves
  • Reduced pump operating costs