Is SERVO DRIVE flex complex?

Is SERVO DRIVE flex complex?

by Matthew Glanfield February 10, 2021

Is SERVO DRIVE FLEX that complex?

I don’t know if you know but there seems to be an idea that SERVO-DRIVE flex is complex and needs lots of different parts for different scenarios. So, I want to try and help make it simpler.

SERVO-DRIVE flex has been designed and tested to work with integrated appliances in tall housings in combination with Blum appliance hinges. However, it cannot be designed to work with every fridge/ freezer, there are just too many. It will also not work with any American style walk-in fridge/freezer or one where the compressor has a deep well, or there is no floor to the carcase. If in doubt it is always worth a call to the Blum Tech Team, see contact details at the end of this article.

What do I need exactly?

You will always need a SERVO-DRIVE flex unit, but the first question you need to ask is “do I need two?”. More often than not you do but let me talk about using single units first. The single kit will work with a single small to mid-size door or half of a tall door. On split doors, you will need to double up on the kits to run each half of the door, for example, one for the fridge and one for the freezer. You must also consider power; each kit will need a power supply which plugs into the wall power socket. So always check the power socket situation first.

What about tall doors?

With a tall fridge or freezer, we always recommend using two SERVO-DRIVE flex units one each at the top and bottom, both units are synchronised, so they operate together to open a tall door and overcome the vacuum seal of the fridge / freezer. They will need the grey wires to be connected so they can “talk” to each other. To power them they should share a single 24w transformer, each device needs a transformer connected to their black power cables. If you have a combined tall fridge freezer you can omit the synchro cable, but you will still need the same parts as a tall fridge freezer.

How do I connect all the cables?

Normally for a two SERVO-DRIVE flex installation, you will need at least 4 connecting nodes, however, if they are synchronised then you will need 6. The grey tails can be connected using the separate standard black cable, but it is best to identify them with insulating tape before you install the appliance. Once installed it will be impossible to tell the difference and connecting them incorrectly will certainly damage the unit.


The flex units do have a sensor in them that will detect the door being pushed, however, this is only practical with a standard small door. Once you start to factor in high doors you will have a certain amount of flexibility which can mean the 2.5mm trigger path is compromised. Therefore, we will always recommend using a switch and receiver, with the switch being right where the hand pushes the door, ensuring the push signal reaches the SERVO-DRIVE flex units. The receiver just clips into the front of the SERVO-Drive flex unit. Please do not forget to install the distance bumpers, they are important to the trigger path too.


According to the catalogue, you can specify the SERVO-DRIVE flex with a dishwasher in an under-counter scenario. However, this is not practical in the UK given our plinth height of 150mm, as for this to work the plinth height would need to be dropped, or the counter raised, either creating issues of one sort or another. Luckily, most dishwashers now come in-built with a knock or push to open door. If you simply must have SERVO-DRIVE flex with a dishwasher then the only practical way for this to work is to build it into a taller housing where space for the SERVO-DRIVE flex is no longer an issue. It is worth checking what dishwasher is specified as well, as the SERVO-DRIVE flex is often incompatible with some dishwashers whose door is on a timed release. All of this can also be true for a fridge/freezer installed under a counter/worktop.

So, you have installed SERVO-DRIVE flex, but it does not work the way you expected, what should you do?

You could run around in circles muttering, grab a cup of tea, or run away? But here is a top tip from us.

The easiest solution is a complete reference run, and by that, I mean the first time the door is operated it will go through a series of opening and closing actions. To determine the settings of the unit, this must be completed without interruption, as to do this would stop it working properly. If at any time the door is not doing what you expect, like for example snapping shut, then always re-run the reference run. This can be done by opening the door and pressing the piston hard and not allowing it to come out for at least 5 seconds. It will then reset, allowing for a second reference run to ensure it runs smoothly thereafter.

Other issues we see are where the fridge/freezer is too deep in the carcase which allows cold air to escape around the seal which will cause problems over time, potentially warping the door. Or simply the appliance was not compatible with SERVO-DRIVE flex, to begin with.

I hope this has answered a few questions about this product but as always if you need further help, then please feel free to contact us at Blum UK Technical.


Hotline: 08002300898

Landline: 01908285700



Written by Peter Sharratt - Blum Technical Team

Matthew Glanfield
Matthew Glanfield


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