Danfoss soft starters

Hotjet company recommends to install Danfoss soft starters on their heat pumps.

What is a soft starter?

It’s an electric equipment. Its function is supported by thyristors. When compressor’s motor is launched, voltage gradually increases. Gradual increase of a starting current will limit current inrushes and reduce the load on compressor’s mechanical part. (On the left - launching process of the starting current without a soft starter, on the right – with a soft starter).


  • 5 years warranty on a heat pump from Hotjet;
  • starting current 40% reduced;
  • no voltage surges;
  • reduced torsion torque at launch, reduced load on compressor’s mechanical part;
  • extended compressor’s life;
  • lower starting current results in cheaper electric installation or smaller size of circuit breaker;

Interesting facts

MCI CH is the first soft starter in the world designed for heat pumps. Soft starter complies with the ЕМС ЕN 60947-4-2 standard for class B of equipment for public premises. Temperature operation limits are -20 to + 40°C. You can also install it on heat pumps outdoors. System integration is much easier comparing to traditional resistor starters.

Technical information

  • Power supply 380-415 V AC
  • Automatic adaptation 50/60 Hz
  • Built-in bypass relay


  • Danfoss MCI 12CH – operating current to 12 A
  • Danfoss MCI 15CH – operating current to 15 A
  • Danfoss MCI 25CH – operating current to 25 A


Konvil OÜ, Hundipea 5, 10416 Tallinn

Phone: +372 660 3637, Fax: +372 660 2106, Gsm: +372 5656 9517

e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. , www.konvil.ee

About us:

The main goal of Konvil OÜ company is to prepare and perform for a customer an optimal and comprehensive energy efficiency solution for buildings of any type: apartment cooperatives, administrative buildings, industrial facilities, private houses. Since 1996, our workers have performed works on more than 150 objects in Estonia, Latvia, Finland and Russia.

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