How to Descale Breville Dual Boiler (BES920) or Breville Oracle (BES980, BES990)
Following the descale isn’t a hard thing to do. Basically we’re draining the two boilers of water, refilling them with descale solution (breaks down mineral buildup in your machine), allow to sit in your boilers, draining again, and refilling with fresh water. You can flush again if you feel necessary.
The reason why this is so controversial is because the descale solution can cause the feedback to breakdown, allowing the steam boiler to switch on dry. When this occurs, the steam boiler can go over temperature. Instead of heating to its normal 130 degrees, it shoots over temp, and the Thermal Fuse can burn out. This alone is painful, however the Thermal Fuse is situated on the lower half of the steam boiler. An experienced technician will take 2 hours to do replace this part, so if you’re taking this feat on yourself, set aside a day on the weekend as you’ll be there for a while.
What do I need?
- Descale Solution
- Torx Screwdriver (this is a star shape)
- Philips Head Screwdriver (the common “+” shape)
- Flat head screw driver (the common “-“ shape)
Procedure
Note: Make sure the machine is turned off. Perhaps i need to advise here that you proceed at your own risk as your machine has live power.
The first step is to undo the Torx screws on the rear, located at the top. Then we’re going to undo the two Philips screws, located next to the tamp, and the other next to the steam wand. Some people choose to flip their machine upside down to do this but I find it unnecessary. Lift the lid to a roughly 45deg angle. You can take the entire backplate off for more accessibility, but it’s not 100% necessary.
Note: Now is a good time to inspect your machine for leaks. Take the backplate off for more access, opening the lid entirely. Get a torch and inspect the top of the steam boiler and around the weld in the middle. Also check the steam valve and for and scale marks around the triac assembly.
Unscrew the two descale port valves on the front (if the machine is on or has been on, beware the steam Putting down a towel on the grill is a great help. The one on the right is for the Steam Boiler, and it should flow freely. If it doesn’t it means you have a block in the drain valve.
The left port is for the Coffee Boiler. To get this to drain you’ll need to remove one of the probes on the Coffee Boiler. Simply pull out the clip, and lift the probe. This will now drain into the drip tray. Give it 30 seconds to finish draining, replace the probe and re-insert the clip. Congratulations, at this point your boilers should be drained.
- Re tighten the descale port screws
- Pour the water out of the drip tray and replace
- Fill water tank about halfway with water, add descale solution and insert water tank
- Turn on your machine
- Let your boilers fill.
- Once filled, let the descale sit in your machine for at least 20 minutes
- If you have a cleaning disc, insert into portafilter, and insert into grouphead.
- Every few minutes, run a shot, run 50-100ml water through the water tap, run steam wand for 5-10s, cleaning all lines of the machine until solution is finished or 20 minutes passes
- TURN MACHINE OFF
- Put down towel and open both descale ports. Take out the Coffee Boiler Probe once more for draining, then replace as per previous step
- Close both ports, empty drip tray and replace
- Empty water tank, and replace with fresh water
- Turn on machine
Now this is where your attention is required. There are 2 pumps inside the machine and they will turn on at the same time. The smaller (and much quieter pump) is the one we need to check, and this fills the steam boiler. If it doesn’t switch on, this is where the thermal fuse can burn out. Simply check that it starts running within 5 seconds of the machine turning on. As the coffee pump is much louder, simply look to see it moving, or put a screw driver on it and feel it vibrate to KNOW it’s running. If it’s not running, or doesn’t run for any reason, disconnect the red wire on the Steam Boiler with some pliers. Let run for 30-60s and re-attach the red wire.
Once your machine is up to temperature, run some water through each line again, cleaning out the little bit of descale that may be left in the pipes. You CAN drain your boilers and flush again, but I find it unnecessary.
Replace the top lid (back panel first if removed), replace screws and the job is done.
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