Number of SERVO-DRIVE flex units

When do I need two SERVO-DRIVE flex units and how can I synchronise these with each other?

This picture shows the SERVO-DRIVE flexSERVO-DRIVE flex is Blum’s electrical motion support system for refrigerators and freezers. SERVO-DRIVE flex therefore allows you to open even built-in refrigerators or freezers in a handle-less kitchen with no problem.

In most cases, you only need an individual drive unit to do so. However, should you want to fit a built-in freezer with a recess height of 1780 mm or greater with SERVO-DRIVE flex, you will require two units.



Due to the stronger magnetic lip seal in freezers with a recess height of 1780 mm, an additional unit needs to be installed under the freezer. In order to achieve the usual opening motion, it is essential that you synchronise both units with one another.
(Caution: should the freezer’s cooling unit be installed below the unit, it will not be possible to synchronise)

How can I synchronise two SERVO-DRIVE flex drive units with one another?

This picture shows two synchronized SERVO-DRIVE flex units

Step 1:
If you have previously commissioned any of the drive units, you must first reset the unit(s) in question. To do this, push the ejection rod in fully for three seconds until you feel a slight feedback movement on the rod.

This picture shows the reset of a SERVO-DRIVE flex unit

Step 2:
In order to synchronise both SERVO-DRIVE flex drive units, connect them to the light-grey synchronisation cable Z10K300A and two connecting nodes Z10V100. The connection points are two cable ends – one black (power connection) and one light grey (synchronisation) – which are located on the back of the SERVO-DRIVE flex units. Insert the light grey cable end of the unit and the light grey synchronisation cable Z10K300A into the connecting nodes and then close the orange lever. The synchronisation cable and the connecting nodes must be ordered separately.

This picture shows the synchronisation of two SERVO-DRIVE flex units

This picture shows the assembly of the connecting node

Step 3:
The next step is to connect the two SERVO-DRIVE flex drive units with the Blum transformer. Now close the freezer door. In order to operate two drive units, you will need the 24 W Blum transformer Z10NE030x. The advantage of this is that you can also connect all other SERVO-DRIVE applications within a kitchen to this Blum transformer.

Step 4:
Now touch the refrigerator door to open it. This triggers a reference run and the units calibrate themselves automatically. During this process, the freezer opens and closes automatically five consecutive times. The reference run must not be interrupted. Should this occur, however, both units will need to be reset and the reference run repeated.

More information on the reference run:

Number of SERVO-DRIVE flex units
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8 thoughts on “Number of SERVO-DRIVE flex units

  • June 29, 2019 at 11:00

    Hi! We wre trying to reset out servo Drive Drive flex, because it does nyt open the fridge door anymore, if we dont push the door multiple times. Pressing the push out stick for 3 seconds is not starting the reference run either. Is it broken, or is there something else we could try? Device has now been on use only for one year, and troubles started already during this spring.

    Thank you in advance!

    • July 1, 2019 at 13:23

      Dear Nina,

      thank you for your message.
      If SERVO-DRIVE flex does not get triggered reliably, the most common reason is that either the sprung distance bumpers are missing, or the gap between the cabinet front and the cabinet side has changed due to door deformation or hinge adjustment. Could you please check first if the gap between the fridge front and cabinet side is 2.6 mm and verify that there are spring bumpers installed (details on these bumpers are found here:
      A new reference run can also help SERVO-DRIVE flex to adapt to the new gap situation.
      If you would like to reset SERVO-DRIVE flex, push the rod for 3 seconds. Please note: If you push the rod back into the SERVO-DRIVE flex housing, you can feel a little resistance on the last 2mm. Make sure you overcome those 2mm by using a little more force. Then, after 3 seconds, the SERVO-DRIVE flex rod will drive out automatically. This confirms a successful reset of the reference run.
      Then, close the fridge door, push on the front and wait until the cycle of 5 automatic openings and closings has finished.

      I hope this helps, otherwise please let us know and we’ll try to dig deeper into this issue.

      Kind regards

  • June 5, 2020 at 9:11

    Hi there,

    I don’t seem to be able to get two units mounted on my fridge synchronized with each other. The synchronization cable is installed, one unit also has the rf receiver. Both units have their individual power adapter. I checked the pins of the connector nodes, and they are fine. I have done multiple resets and reference runs, but still no synchronization. Can you clarify what is going wrong?

    • June 5, 2020 at 10:41

      Dear Veysi,

      your description is very comprehensive and thanks to that, it is quite clear to me what causes the issue. The problem is that you are using two individual power supplies. Each power supply has it’s own electrical potential, which is why the synchronisation does not work.
      If you want to synchronise two units, please use the 24W power supply (important notice: NOT the 12W UNO-power supply as it is only designed to serve one unit at a time), and connect both black power cables of the units with the 24W power supply. Then, perform a reset of both units (each one has to be resetted individually.

      I hope this helps, otherwise please let me know or get in touch with one of your local Blum representatives found here:

      Best regards

  • August 11, 2020 at 0:56


    If I open the fridge then I really need to pull to open the fridge. We have two units because our fridge is above 178 cm. There is also a loud bang from the lower unit. When the door is opened further then suddenly the lower units ‘bangs’ back into the slot. It seems if the magnet is pulling the ejection rod outside and then – if the ejection rod can not go further – is releasing it, causing it bang back into the slot.

    We have the magnet on the upside and downside of the fridge door and we do not have the spring bumpers installed.

    Is the ‘bang’ normal or should it be more quiet?

    Best regards,

    • August 11, 2020 at 19:02

      Hi Paul,

      actually, this only happens when the unit has not extruded by itself so I highly suspect that only one unit is working at the moment. There are a couple of possible reasons for that: Either the lower unit is not connected to the power supply, or it is not synchronised with the unit on top. As this is something that a specialist would have to check, is it possible that you approach the supplier of your kitchen, or the installer who has installed your kitchen, to perform a check if the units are synchronised and both connected properly to the power supply?
      Besides, the spring bumpers are highly necessary for SERVO-DRIVE flex to work properly, so please also ask for installation of those. After all the changes, it is important to reset the reference runs of both units.

      Please let me know if there is anything else we can do for you.

      Best regards

  • September 24, 2020 at 7:55

    Hi! When syncronizing two units and using a 21P5020 wireless remote control, does only one of the Flex units need a Z10C5004 reciever, or do i need two?

    • September 24, 2020 at 10:06

      Hi Frode,

      one receiver is enough. But please don’t forget to synchronise the units using their light grey cable at the back of the housing 🙂

      Best regards


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