How to avoid blocked circulator pump

If the circulator pump or system is filled up with water for the first time and the pump is stopped for a longer period of some weeks or months, it might happen that the pump is not able to start.

How to avoid blocked circulator pumps?

» For end users, we suggest to keep main power on the circulator pump.

  • Do not remove the main power. Let the circulator pump run.
  • A typical high efficiency pump consumption in the heating season would be in average < 16W.
  • HE, HES, HET high efficiency pump. Set in PP or CP will go down to 5W during summer period.

» For manufacturers, we suggest to change the control.

  • Keep the circulator pump running with the main power on. No possibility to remove the power to the pump.
  • Set the circulator pump in stand-by via PWM and cycle the pump each 24hours like in Combi Boilers.

» Notice for installing and commissioning the circulator pump

  • We recommend to have the circulator pumps operating constantly after installation. This ensure elimination of lime precipitation in the bearings for the whole lifetime of the pump.
  • For circulator pumps installed in newly constructed or refurnished houses and apartments, it’s recommended that the pumps are allowed to run for more than one hour after installed. It is to secure that the air is proper vented from the heating system and pump.

How to deal with the blocked circulator pumps? 

There are two de-blocking systems. Circulator pumps usually feature one of them or both.

» Deblocking software(Automatic de-blocking function)

Continuously restarting the pump after 1.33 seconds with max. torque of 24.8 Ncm. New generation of high efficiency circulator pumps usually use it, such as Grundfos Alpha & Magna, and Wilo Yonos & Stratos. Plastmax HE & HET


» Deblocking device (Manual de-blocking)

Manual deblocking device, access from front side without demounting the control box. What you need is only a screw driver. Deblock the rotor shaft by tuning the screw driver clockwise and then anticlockwise. Typical models of circulator pumps usually use it, such as HES & LE


The above two systems are the shortcut solutions for blocked circulator pumps. If they still don’t solve the problem. You have to switch off the main power, Remove the pump head and loosen the Impeller by hand. Then Mount the pump head and start the pump.