Post By WarrenK
Post By level3ninja
Breville 870 pressure drop
Hi all, looking for some expert advice.
I've got a Barista Express 870 coffee machine that's about 5 years old and been used daily. It's becoming increasingly difficult to pull an espresso with the pressure gauge in the 'espresso range', especially a double shot. The only way I've been able to get any pressure is by putting the grinder on the finest setting and packing the coffee as tightly as possible, but this shouldn't be the case and I feel is only making the problem worse? It used to get pressure with a medium grind setting and only light tampering.
The grinder also pushes out way more than required, even on the minimum setting (not sure if that's a related problem). The machine also has a small crack on the top.
Is it normal for these machines to just wear out, and need replacing? Or is there something I am doing wrong, or seals I need to/can replace? I've given it a clean out but hasn't solved the issue..
Anthony, are you using fresh roasted beans? I had similar problems with supermarket beans, until the penny dropped.
Does the ground coffee look/feel the same size as it used to on the medium setting? Or does it now look coarser? The fact that the grinder is giving you more coffee in the same amount of time suggests it's grinding coarser, which would also fit the other symptoms.
If you run a shot without the portafilter, does it look like a normal amount of water? Try removing the shower screen and measure how much water you get in 30s.
Yup, changed to ALDI beans the last run to try them. Grinding them right before adding them..
Originally Posted by WarrenK
Ah, good point - yes may be something wrong with the grinder? As in it's just not stepping down to the fine setting? I did take it apart to clean it and maybe I haven't put it back properly. The felt had deteriorated so will replace that and see if that's causing the issue. Thanks!
Originally Posted by level3ninja
Last edited by kase; 28th May 2019 at 03:52 PM.
I recently serviced a friend's 870, and don't remember any felt? I did recalibrate the grinder to grind finer then theirs was able to previously.
There's a felt washer in the grinder but seems like it deteriorates pretty easily/quickly:
I suspect I may need to recalibrate, is it a DIY thing - will search the web for some instructions anyway, thanks!
It's relatively DIY, bit fiddly but if you're patient and gentle there's no reason you can't do it. I'll have to see if I can find the photos I took while doing it.
Ok, so I'm missing some photos, but I'll try and describe it all.
DISCLAIMER: Have your licensed electrician / appliance repairer do this for you, have them take lots of photos along the way before removing/undoing anything so they can put it back together correctly.
Empty the hopper of beans, then grind through any remaining beans / remove them with a vacuum etc. You need the grinder to be completely empty from top to bottom.
Once you have the top cover off, adjust the grinder all the way to the finest setting (1), and remove the screw in the top middle of the silver grind adjustment wheel.
There is a small scalloped section on the bottom of the silver grind adjustment wheel to allow you to get it in and out, you need this to be lined up properly or it won't come out. Take note of where this scalloped section is and wiggle it back into place each time with that section lined up, then lift the wheel and rotate it above the white cog until it's in your desired position.
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Once you remove the silver wheel this is what you'll see. The red circle is where the screw holding the wheel down screws into. This is where we'll be making our changes. The big black cog is the actual grind adjustment, you turn that and it screws up and down to make the grind coarser and finer. The white cog just takes the input from the silver wheel and then turns the black cog. The white wheel has a stopper on it (underneath), so by changing the position of the stopper compared to the black wheel we move the grinding range as a whole finer or coarser.
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In the photo above there are 2x screws circled, there are also 2x more at the back. In the photo I have already undone the screws and lifted the grinder assembly up for better access (the arrow is pointing at the hole the right circled screw goes into). You will have to undo all 4x screws before carefully lifting the whole assembly up until you can access the clip at the bottom of the while cog. Be careful of the blue and orange wires you can see near the left circle, they go around part of the assembly and you will need to check they're in the right place each time you lift the assembly in and out.
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In these photos you should be able to see the clip at the bottom of the white cog. Before removing it make note of the direction it turns, and where it's limits are at both ends. We're going to turn the grinder all the way finer.
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See the two ridges in the above photo, they're what hit to give the grinder it's limits (both fine and coarse). From memory rotating the white cog and silver wheel clockwise makes the grind finer (the following directions assume this, reverse if not the case). With the white cog as far clockwise as it will go, unclip it and lift it up enough so the teeth of the white cog and black cog don't touch, turn the black cog anticlockwise until you can feel the burrs touching, then back it off clockwise slightly. Push the white cog back down until it clicks, being careful that the ridge on the white cog is positioned so that it's almost hit the black ridge to stop it from going finer.
Carefully put the grinder assembly back down into position, and check the blue and orange wires are as they were. Tighten up the 4x screws, reinstall the silver wheel and screw it in place (be careful to rotate it back and forth once it's in position but not screwed down to check that the min/max line up with where the wheel stops turning). Replace the lid of the machine and do up its 5x screws holding it in position.
You have now completed the first adjustment, you will need to put some beans in the grinder and do a test run. Depending on the results of this test run, if you need to go finer you will have to repeat all above steps again, except when turning the black cog all the way fine don't back it off etc, other than that all other steps are the same each time. I had to adjust it so that without coffee beans pushing them apart the burrs were touching, but once the beans were in the burrs didn't touch and it ground fine enough for espresso.
Feel free to PM me if you want more help, I can probably talk you through most of it on the phone. Or if you're in Sydney you're welcome to bring it over and we can do it together (I'm in West Hoxton).