First, my apologies for the length of my first post to the CoffeeSnobs forums (it's an instruction guide, and I hope you find it informative for descaling ).

I've owned my BES920 dual boiler for just over a year now (purchased May 2017), and just did my first descale a week or so ago. After headaches, almost one or two rage quits, a great amount of trepidation, and a phone call to a frigging awesome individual from a repair shop in QLD, I successfully descaled my machine without issue! Breville were more than useless in this process, they didn't know their machine particularly well when I called them, before reaching the individual from the repair shop who will henceforth be known as Ďthe guruí (for reasons that prevent them from being inundated with distressed, well-meaning callers).

I wanted to provide a run through on how I did it, in the hope that it might help someone else who gets into my position too.

I followed the instructions that Breville included in the box, and the ones that Breville sent to me by email after I called them and explained my issue, however they weren't updated for the software version that I have. Getting into descale mode was the same for previous firmware versions (let your machine cool for an hour if you have used it, and then press and hold the one-cup button, and then press the power button whilst holding the one-cup button, then scrolling through to descale (dESC I think), and selecting it).

I have the latest firmware, and this changes things (i.e. the button that lights up, and what the LCD panel shows). In the instructions I had, the LCD reads PUSH, and the manual button lights up. On my firmware, the LCD panel is lit up, but blank, and the one-cup button is lit, not the manual button. This is one of the changes with the latest firmware. Pressing the one-cup button starts the descale process, simple I know, but I didn't want to do anything at first as it was different from the manual (sigh).

Anyway, here are some pointers/instructions that I hope helps with Breville's slightly 'lack of informationary' instructions:

*** (IMPORTANT) ***
1. After the 1 hour of cooling, when opening the boilers (first, the right screw for the steam wand boiler, then the left screw for the espresso boiler), turn the screws very, very slowly (* itís INTEGRAL that you do this after the second and third boiler flushes, when the pressure is highest, but start from the first ). After the second boiler empty (after the descale has been run through, as you have emptied the boilers once already after the cool down process), if you turn the screws quickly, especially on the steam wand boiler (i.e. right screw), you can blow the fuse and element if turning too quickly. The guru said this was the main culprit with those buggered boilers after descaling, in his experience. Just go slowly, gently, caressingly, enjoy the moment.

Also, you are going to do THREE (read 3) flushes in total during descale. The first is the descale solution. And the next two is just water. This should solve you poor peeps not being able to get out of descale mode after powering back on (again, another piece of advice from the guru). The machine is waiting for the process to run 3 times.

*** /(IMPORTANT) ***

2. I used a liquid descale solution, which uses a 1:10 mix (100mL of solution to 1L of water). I happened to find mine from The Good Guys in QLD (not a plug, just a FYI in case you hunt for one yourself in a brick-and-mortar store instead of online).

2. (a) The guru let me know that each descale run of 20 minutes uses approximately 1 litre of liquid (and remove your water filter from the tank too, of course). The manual states to fill the water reservoir to max, which is about 2.5 litres. You waste descale solution by filling it to the max line. The guru suggested filling a bit over 1L just in case, and I filled to 1300mL (using about 120mL of descale solution), and it left about 100mL or so of liquid (I didn't measure it) after each flush.

3. Press that lit-up manual or one-cup button to start descaling, and once you start the descale, set a timer for 20 minutes if you plan to walk away from it. It doesn't beep or anything when it finishes, it's a silent bloody ninja. After finishing, the screen is blank again (or reads PUSH, I assume) and the manual or one-cup button is lit up. ***IMPORTANT*** When opening the boilers, turn the right screw for the steam wand very slowly (you don't want to blow anything). It will start to hiss, and sploosh, and then it's all over rather quickly (a bit anticlimactic really). Then do the same for the left screw. It won't make as much of a to-do. Make sure you have your towel over the tray unless you have asbestos hands. Do it anyway, just in case, as the water and steam are of course very hot. Remove the drip tray after the all of the water has drained (you should see that it stops flowing after a short while).

4. Remove the tank, and empty the remaining descale water from it, and then rinse it thoroughly (even get in there with a sponge, maybe a little detergent, and get that descale solution, and its smell, out). I neglected this step and did a whole new descale process with just water as it was smelling a little too 'descaley' for my liking.

5. Press the one-cup button (or manual button, for you old skool peeps) to start the next descale for 20 minutes. (* You are going to do this for a third time after this, the machine is configured to do 3 flushes, 1 with descale solution, and 2 with just water).

6. Repeat steps 3, 4 and 5 (*slowly open those screws!), and give the water tank another rinse/wash, whatever floats your boat. Fill it back up with 1300mL of water, and pop it back in.

6 (a). Get your new filter ready (soak for the last 5 minutes of the 20 minute descale).

7. After your third and last flush, you will be back to a blank LCD and manual/one-cup button, same as the previous times. Now, pop your soaked filter in, fill up the tank with clean water TO THE MAX, and pop it back in. Just press the power button at this stage, and it will start back up. All things going well, and it 'should' be at this stage, your machine will heat back up to 93 degrees. **Note, you will probably get 3 beeps on the steam wand when you impatiently activate it after its heated up (okay, maybe thatís just me). This means the steam wand boiler is still heating. Wait 5 minutes and give it another go, and it should be full steam ahead (ha, see, I make funny!).

I hope that this post is informative, and thorough, and a good accompaniment to the manual, forum posts, and YouTube videos, that show this process.