NK Reparatur

We are official dealer of Nielsen Kellerman for Germany since March 2017. Accordingly, we also offer repairs for NK products. By the way, we explain common problems right at the bottom of this page.

If you have a problem with a device from NK, please send it to us. We check the unit and initiate afterwards the necessary steps.

Please follow the procedure below:


  • Download the form "Reparaturformular Nielsen Kellerman"
  • Please complete this and describe the problem as accurately as possible. Important please be sure to insert the serial number on the form!
  • It is absolutely necessary to complete a separate form for each repair
  • If you want to claim a warranty repair, please attach the sales receipt
  • Pack the items carefully and attach the forms and if necessary the receipts
  • Send the package to: 4row GmbH & Co. KG, Müggelseedamm 70, 12587 Berlin, Germany
  • We will contact you. Please expect between 3 - 4 weeks itte rechnen Sie mit 3 - 4 weeks processing time. Depending if your product needs to be shipped to America.

Warranty periods

  • 5 years - Blue Ocean
  • 2 years - StrokeCoaches and SpeedCoaches
  • 2 years - Interval stopwatches
  • 2 years - Batteries and accessories

Battery discharges quickly - SpeedCoach GPS

The SpeedCoach GPS watches with the serial numbers 2300176 to 2363069 sometimes have problems with the battery life. Please check that you have at least version 2.21 installed. If the current version is lower, please install a software update first and check the functionality again. If there are still battery problems after that, please send the device in as described above.