Gaggia TS – Controller Fault Red Neon Light Permanently Lit

No coffee today due to a Gaggia TS fault.  The red neon on the front panel is permanently lit (usually meaning the water tank is empty).  Unfortunately for me it is completely full.

I even tried a pinch of salt in the water to see if it would increase the conductivity and also removing one of the metal strips in the tank and holding it in contact with the other to see if that fooled the controller into thinking there was plenty of water.  No luck.

Next thing to check is the wiring.  Hoping for a fault here, as a break in the wires from the sensing plates to the controller could save some expense. Sadly these were fine also.

Only thing left was to replace the controller which is low down on the right hand side.

Once unbolted, the connections can be numbered for easy relocation to the replacement controller.

The connections to the tank level probes are on pin 10 (earth to the boiler and to one of the tank probes), and 8 (to the other tank probe). Connection 9 is to the boiler probe.

The new controller is a Giemme RL0 1E/1S/4C/F (also coded as 01.03.0036).

Once in, everything was back to normal.

In case you need to check your own controller, the video below shows how it should work.

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31 Responses to Gaggia TS – Controller Fault Red Neon Light Permanently Lit

  1. Gaggia TS – Controller Fault Red Neon Light Permanently Lit | Coffee Machine Service

  2. Alex says:

    Hi Steven, love the website and I have found your information very useful. I have just purchased a TS from eBay and it needs a new controller as the last owner managed to burn it out. The power switch lights up and the group head heats up but that is it, nothing else works no doubt due to the controller. Can you point me in the right direction so I can get it up and running please

    Many thanks


    • admin says:

      Hi Alex,

      I was looking at that machine on ebay myself. I think you got a great buy, as there is one on there at the moment for £300 auction with a BIN of £600 !

      A good working one is worth about £250 I would say.

      Can you let me know why you think the controller is burnt out? Obviously the boiler is not heating, but is the fill-function working? Is the pump working?

      PS: We will have the controllers back in stock in about 10 day’s time.


  3. Alex says:

    Hi Steve, thanks for replying. In answer to your queries no pumps are working, boiler does not fill and after inspecting the controller it does look somewhat damaged by heat. By the way what is the cost of a new controller?



    • Alex says:

      Hi Steve, just to let you know that I have replaced the transformer and the capacitator and it still does not work. Probably be easier to replace the CPU in its entirety. Can you let me know when they are in and the cost please.


  4. Gareth says:

    Hi Steve,

    Love your site and I’m also a big fan of the TS. I’d love to get a spare controller if it’s something you sell. Can you point me in the right direction or drop me an email and I would be happy to order one from you.


    • admin says:

      Hi Gareth,

      We sell the controllers for 65 GBP inc VAT (most online sources have them for over 100 GBP).

      P&P is 3.99 GBP (to mainland UK).


  5. Ada says:

    Hi Steve
    I did not know how to contact you, can you send me a link to your store for Gaggia TS parts.

  6. Ada says:

    Hi Steve
    Sorry for late answer, now i need heating element for TS.

  7. Ada says:

    It’s ok, i’m find it.

  8. Gene Price says:


    Glad I found this site and this post. I have an issue almost identical to yours on my 4 year old Gaggia TS, except that my low water light does not come on until after I have had the machine on for 15 minutes or so and made a couple of espressos. Then for no apparent reason, the light comes on and the machine shuts down. If I turn it off and let it cool for a while, I can turn it back on, wait for it to heat up, and it will work again for a short time. I’ve tried cleaning the copper plates in the water reservoir, but it does no good. I’ve also checked the various connections, but I really do not think it is a loose wire issue because the fault is so consistent and predictable. Based on this post and a couple of your other posts, I have to conclude that it is the controller. Do you have any other thoughts? If not, how can I go about getting a replacement controller?



  9. Gene Price says:

    OK. Thanks. I think I have found another source.

  10. Malcolm says:

    My TS has an issue where the light will flicker on and off. Always seems to be when removing or inserting head. It can also do this whilst making a coffee and a gentle tap (sometimes it flickers on and off a lot) on the side will make it work again. Ideas? Also where can I purchase some spares that you refer too?

    • admin says:


      I assume you mean the light on the front that shows when the water tank is empty?

      As the light will normally be unlit, only lighting when the tank is empty, I would start with checking the wiring to the two stainless steel electrodes in the water tank. These connect to the control unit on the left side of the machine looking from the front.

      Other than that, given the symptoms stated, I would suspect the control unit.


  11. Nick says:

    Hi Steve , I have this problem on my TS and have checked all the wiring so am left with a controller fault. Having checked all the soldering I can see and re-flowed the joints to the relays (with no improvement) I think I’m going to need a new controller. Can you still supply these? your ebay page (above) has expired.

    Many thanks


  12. Gordon Moore says:

    Steve, I am having an issue with my TS.
    It keeps flickering power on/off. Not sure what this could be. I have taken the power cable out and blown the connections out.

    • admin says:

      Do you mean the neon in the red on-off switch near the drip tray is flickering?

      I would:

      Try a different cable and wall power outlet.
      Wiggle the new cable in the socket under the machine to see if it has an effect.7
      Check the connections on the reverse of the inlet socket inside the machine.
      Check the connections on the reverse of the mains on-off switch inside the machine.


      • Gordon Moore says:

        Thanks Steve.
        Had a look inside and it looks like the copper capillary tube for the pressure gauge was touching the connectors on the on/off switch and cooking them.

  13. Greg says:

    Hi Steve
    Stumbled across your website. I’m based in Australia, but think I’m having an issue with my Giemme controller RL0 1E/1S/4C/F. Its 15 odd years old so held up pretty well. I’m getting an issue where the boiler is only refilling intermittently when taking hot water from the hot water tap. I’ve checked all connections and all are fine. Also replaced the boiler fill probe & teflon sheath. Tested by removing boiler fill probe connector (and this is when the boiler should keep refilling) and it only works sometimes.

    Am I right in thinking that the relays on the control board are stuffed? Could it be something else on the control board?

    • admin says:

      My guess would be the relay on the control board which powers the fill solenoid.

      To help decide, can you hear the relay operating EVERY time, but the fill solenoid only operating OCCASIONALLY?

      This would point to dirty contacts on the relay.


      • Greg says:

        Thanks Steve. I’ll have to run some tests again, with the control board opened up so I can hear it properly.
        Worth pointing out that in the rebuild I’m currently trying to finalise, I’ve replaced the solenoid so it’s brand new (old one had boiler leak directly on it).

        Is it just the one relay on the control board that needs replacing? I’ve tracked it on board itself as Omron SPNO Non-Latching Relay PCB Mount, 12V dc Coil, 10 A and ordered two online.

        By dirty contacts, do you simply mean the contact points that the wires connect to on the control board? The connections to the board and the contacts appear to be ok (no oxidisation etc). I could always try giving them a clean up as well. What’s the best method you’d suggest?

  14. Greg says:

    Hi Steve. My control board differs slightly to the one shown in that thread. Same model but I have 4 relays. K2 being the pump, K3 the solenoid, K1 the L (assume this is the light?) and K4 the element. K2 and K3 don’t appear to be on the same coil. I also have 4 wires in the low voltage side with an extra ground for the water tank level.

    Still thinking it’s K3 that is my issue. Thoughts?

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