Gaggia Classic - Flow Control Dimmer kit

Flow control dimmer 1

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Our flow control dimmer kit is designed to fit into any Classic that has a TopBox fitted, or any Classic that the owner is prepared and capable of drilling a hole in the case to expose the control knob.

With the flow control dimmer installed, the Classic pump output can be varied from zero to full flow, by rotating the control dial. It should be noted that the dimmer will control the FLOW of water from the pump - and NOT the PRESSURE.  Pressure is a function of the water flow and the puck resistance, so usually when the flow is increased the pressure will similarly increase, but it's impossible to say that the dimmer will give 0-9 bar control as peak pressure is controlled by your OPV and the resistance to flow generated by your coffee puck.  It will give 0-?? bar control - and the ?? could be anything, depending on your coffee puck and your OPV status.

Using this flow control dimmer you can very effectively do a low pressure preinfuse, then shut the pump off completely to allow the puck to bloom, and then slowly ramp up flow (monitoring pressure with our brew pressure gauge if you have one installed) to emulate the flow and pressure characteristics of many other machines.  Flow and pressure control are typically features of much more expensive machines - now you can have this exciting and very useful feature in a Classic.

The flow control dimmer kit contains a control board, housed in a small plastic mounting case with a remote potentiometer control knob that has a knurled aluminium finish and is a nice size to allow simple yet precise control.

The control board and associated power resistor is installed within the main case of the Classic, with only the small potentiometer based control knob being installed within the TopBox (or elsewhere if a suitable hole is made).

With TopBox mounting, the knob can be on the left or right of the machine and no modification or drilling to the TopBox is required.  The product image gallery shows the flow control dimmer fitted within a Classic that has a TopBox with PID, brew pressure gauge, and flow control dimmer - though these images are purely to show what a more fully modified machine may look like.

We provide all wiring, and various associated pieces of mounting and securing hardware.  

No cutting or irreversible changes to the Classic are required and only simple tools are needed to complete the installation of the flow control dimmer kit:

  • Screwdrivers
  • Pliers

Installation is relatively simple and quick - not quite as simple as our OPV kit, but much simpler than a PID install, and would take most people around 30 mins to complete.  It can be removed and the machine reverted to standard configuration/ operation just ask quickly.

Full installation instructions are provided.

This kit is suitable for all Gaggia Classic models (110V or 220-240V) of any age - though see the note below concerning the RI9403 model.


RI9403 model: Whilst our brew pressure gauge kit is not suitable for the RI9403 model, this flow control dimmer is – so you can install it on those machines if desired – though output may not accurately reflect the sound of the pump due to the brew valve installed above the shower screen, which won’t open below around 5 bar. However, you should be able to control the output above this point if desired.

This kit contains:

  • Flow control dimmer control board
  • Plastic control board protective mounting case
  • Remote rotational potentiometer control (wired)
  • Control extension lead
  • Power resistor
  • Black aluminium finish control knob
  • Stainless steel knob mounting washer
  • Pre terminated and colour coded connection wires for "plug and play" installation
  • Self-adhesive control board and resistor mounting hardware
  • A link to download the installation instructions

DISCLAIMER:  The installation of any of our parts or kits, and any modification of any espresso machines undertaken by reference to our installation and/or user guides, should only be conducted by persons with proper electrical safety knowledge who are capable and qualified to undertake such work and modifications.  Many of the components within espresso machines operate at high temperature, high pressure and with mains electrical voltages at high current in the presence of water – any of these could cause serious personal injury, shock, burns, fire, explosion, other property damage and possibly death.  We shall hence not be liable for any damage to property, personal injury or other loss caused by the improper or incorrect use of the aforementioned installation and/or user guides or the provided kit(s) or any of those kit’s component or constituent parts.  By commencing installation of our kit(s) you agree to accept all liability associated with the modification of your espresso machine, and agree to hold us in no way responsible or liable for any loss, damage or injury howsoever, wherever or whenever caused.  You further agree to indemnify us and our agents, officers, directors and employees, immediately and on demand, against all claims, liability, damages, costs and expenses, including legal fees, arising out of any installation, use, misuse or failure of any of our kits or component parts thereof.

Super easy to install. It's an enormous upgrade for a small cost - the quality of shots is several times better than before. I had no problems with the install or usage. Manual controls are always fun as well.


Pros: It works! You will get full flow control through this kit. Cons: There is a lot of jank around installation (and configuration if you are in a 110-120v region.) Components fit together such that some important parts cannot be disassembled without risk of destroying the parts. IMO there must be a better way of doing this, such that installation errors, component failures, etc. don't automatically lead to needing an entire re-order. If you are longing to experiment with all sorts of flow control using your Gaggia, definitely go for it. Personally, the jank has made me reconsider whether I truly want to play around with this. [SoC Feedback] This is entirely by design - we secure the electronic control board in our plastic enclosure using the plastic mounting clips for safety reasons (mainly to prevent accidental electric shock from touching the exposed board). It locks in once the kit has been tested and properly assembled; and if any part ever needs replacing you can buy ALL parts individually from us as spare parts, meaning that you would NEVER need to re-order a full kit to repair a single component failure. If parts are ordered that require new mounting clips then we will supply these on request, though they are readily available globally anyway should they ever be needed. Most people find this kit one of the quickest and simplest to fit - typically taking 15-30mins from start to finish (even with setting the adjustment screw, which is the additional step required for 110V machines).

Biscuits mystérieux

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