The Grundfos UPM3 Solar 25-75 pump is manufactured in France and is designed for use in thermal solar systems. This model of the circulatory pump with a wet rotor is known for its high energy efficiency and good performance, making it one of the best devices for operation in solar hot water systems. One of the main advantages of this model is the ability to connect external control devices with PWM (profile C), as well as the option to operate in constant curve mode without the need for external control circuits. The rotational speed has 3 adjustable levels. The device’s housing is made of gray cast iron, which houses a stainless steel rotor supported by metal-graphite bearings. The device itself weighs only 1.9 kg. Only chemically inert and high-temperature resistant synthetic materials are used to manufacture the impeller, ensuring the cleanliness of the pumped liquid. This choice of materials and design allows for long-term operation of the pump without deterioration of its technical characteristics or failures. The dimensions of the Grundfos UPM3 Solar 25-75 installation (length) are 130 mm. Both horizontal and vertical installation is allowed. Threaded connections G1½” are used for connection to the system. To simplify installation and connection to electrical circuits, the supply package includes a power cable and a PWM control cable.
The Grundfos UPM3 Solar 25-75 provides a liquid pressure of 7.5 m with a flow rate of up to 3.4 m3/h. The power consumption is only from 2 to 45 W at a supply voltage of 220 50 Hz. The temperature of the pumped liquid should be within +2 to +110°C, but short-term temperature increases up to +130°C are permissible.