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How to Descale the BES900/BES900XL Breville Dual Boiler

What you need

    • There are 4 screws holding the top of the machine on. Two torx screws in the back, and two philips screws under the front overhang of the machine. Remove these, and then CAREFULLY lift the top off, minding there are wires attached to the top. You should be able to prop the top along the back of the machine and leave it there.

    • Optional step! You can go straight to descaling the boilers if you wish to skip the cold path leading to the boilers. This area is much less likely to have scale and it will save a lot of time. Recommended if you've already done a complete version in the past.

    • First, ensure your machine has full boilers. To do this, simply turn it on and wait a few seconds. If the boiler detects it needs to be topped up, the pump will run. Once this is done, turn the machine back off.

    • Empty your water tank, and mix up your preferred descaling solution per package instructions. Add this to your tank, and place it back into the machine.

    • Turn your machine on and wait for it to get to temperature

    • Once at temperature, either run the clean cycle or hot water for enough time that you note the tank level has dropped. Important At this point, we want to turn the machine off. All we are trying to do with this step is get descaler into the plumbing leading to the boilers.

    • Your machine is off, right? Remove the water tank and reserve the remaining descaler for use in the next step. Clean and rinse your tank and fill with fresh water and replace.

  1. How to Descale the BES900/BES900XL Breville Dual Boiler, Descaling the boilers: step 3, image 1 of 3 How to Descale the BES900/BES900XL Breville Dual Boiler, Descaling the boilers: step 3, image 2 of 3 How to Descale the BES900/BES900XL Breville Dual Boiler, Descaling the boilers: step 3, image 3 of 3
    • We've now got some descaler working its magic in the path leading to the boilers. (Unless you skipped the previous step) Now we need to get inside the boilers to clean them.

    • Unplug your machine.

    • On the brew boiler (in front), there are two probe ports towards the front of the machine with blue wires attached. On the steam boiler (the other one), there are 3 probes. Take a picture of these.

    • Remove the wires on these probes. You should be able to use your fingers, but you might gently use the pliers instead. Remember the wire order.

    • Remove the clips retaining the hoses. Simply insert your needle nose pliers into the little loop and work them out, careful not to drop them.

    • Gently pull the probes out, noting that the short probe on the steam boiler goes in the port on the right. You'll want to scrub these or soak the rods in descaler and set them aside for later.

    • It's siphon time! Place a container (anything around 2 liters or more) below the level of your machine. I simply put a big measuring cup on a chair.

    • Insert one end of your tubing into one of the boiler ports and slide it down until you feel it reach the bottom. Start suction on the other end of the hose until you see the water close to your mouth. Place your finger over the end of the hose to prevent the water draining and drop the end of the hose into the container and let go.

    • The siphon should work to remove all of the water from your boiler. Repeat this on the other boiler. Note You need to ensure the end of your tubing gets to the bottom of the steam boiler as it can easily hit the heating element and stop.

    • Tip: You can use a bamboo skewer or similar to straighten out the tubing and run some very hot water over it for a minute. It should stay straight enough after that to work great!

    • If you've gotten to everything out of the steam boiler, you should have some murky, scaly water. Using your flashlight in one of the ports, you should be able to see if you've emptied the boilers.

    • Now place your funnel in one of the ports, and carefully pour descaler into each boiler until just about full. The steam boiler is about 1.5L and the brew boiler is .5L.

    • Now you have an option - You can let the descaler do its job and wait, or you can replace your probes and wires, turn on the machine to heat it up and carefully run descaler through the steam wand, group head and hot water valve. You just need enough to saturate the paths and sit. Turn off the machine

    • Wait 30 minutes or so. Repeat the siphoning process for both boilers. You should hopefully see the solution is discolored (it depends on the descaler). Check the condition of the boiler elements with your flashlight. You may want to pour new descaler into the boiler if they're not quite sparkling. Heat it in the microwave first.

    • Once you're satisfied with the state of your boilers (it may take several drainings depending on scale), drain a final time, and refill both boilers with clean water. You can be extra and used distilled if you want. You'll need to drain and fill a couple of times here as well. You just want all of the descaler rinsed out.

    • Fill each boiler about half way - we still need to clear the water path prior to the boilers in the next step. Replace the probes and wiring and turn the machine back on. If you didn't perform the optional cold water path descale, you can skip to the final rinse!

    • By now, the descaler should have done its job on the path leading to the boilers (scale shouldn't be much of an issue where the water is cold here, but it can't hurt)

    • With the machine heated up, and fresh water in both the tank and in the boilers, run your brew cycle, hot water tap and steam until the water level in the tank reduces a bit. We should now have sparkling clean lines leading to the boilers. However, the boilers now have just a bit of descaler mixed with the fresh water. Turn the machine off

    • Since the boilers never completely drain, we have to drain and rinse them one last time. Repeat the previous step to do this, and replace the probes and wires for the final time!

    • Run a full tank or two of water through your machine, ensuring you don't see any leaks from any of your boiler fittings. It's a good idea to taste the hot water out of the group to ensure it is pure hot water.

    • Refit the top of the machine and replace the screws. Nice job, you're done!

Conclusion

To reassemble your device, follow these instructions in reverse order.

3 other people completed this guide.

Damian S

Member since: 02/13/23

223 Reputation

1 Guide authored

2 Comments

Exelente descripción de como solucionar el mayor problema de BDB900x. Ciertamente una magnifica maquina sin lugar a dudas. Breville tubo cientos de quejas y demandas por este problema de la complejidad del desescalamiento en los boilers. Termino editando la versión actual del BDB920x que tiene en la parte inferior derecha, 2 drenajes para cada boiler, y así proceder sin tanto cuidado de abrir la máquina, y llego a la opción de que todos los poseedores de la maquina 900x, mandaran a las oficinas centrales su vieja maquina con 300 dólares, y les reponían una nueva del nuevo modelo BDB920x.

En Mexico NO existe mas este representante de Breville, así que los que tenemos estas maquinas de primera edición BDB900x tenemos que arreglárnosla. Existe ausencia de información de como hacerlo, ya que en USA, simplemente les cambiaron las Maquinas por nuevas, y los 2 videos tutorial es en you tube, son cansados y algo malos, pero se les agradece. Esta descripción es EXELLENTE, orienta y resume lo principal es facil suerte

salvadorvillazon - Reply

Thank you for your support! Breville is no longer replacing the BDB900x with anything now! Even in the US. It is considered 'end of life'. So there is no more support. It's the main reason I made this guide - because I had to!! lol. Gracias!

Damian S -

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