Fixing my espresso machine

Food Dec 19, 2022

How to fix your machine when it suddenly doesn't produce any pressure

This post is for everyone with a Breville/Sage BES870XL (Barista Express) or the brand I got in the Netherlands, a Solis 115A (Grind and Infuse), which is an (almost) identical machine. I say "almost" because some screws are in a different place, but that might also be because my machine is of a newer revision and newer Breville machines have the same change. This post is also for myself, so I can read back how to open this machine.

The machine

Some history firts. I bought my espresso machine second hand about 6 months ago (June or July 2022). The previous owner sold it relatively cheap, about half the listing price, because they needed a smaller machine rather quickly. It came nicely packaged and although it looked obviously "used", it had some scratchmarks, little dents and some printed text had faded, it worked perfectly. The first espresso I made with it was amazing.

The first thing I noticed was that the basket rotated to far. The handle didn't came straight out towards me, but rather at an angle to the right. A closer look revealed a worn out group head gasket, which was sourced within a few days from a local parts dealer.

Then I noticed that water accumulated on the table the machine was seated on. Damn, something is leaking. Looking inside the machine (more on that later) I saw where it was coming from; the 3 way overpressure valve. I again sourced it together with some new o-rings, just in case. And, problem solved.

The issue

Now, December 2022, again something weird was going on. This time, when I pressed the button to start brewing, the pump started working, the needle of the pressure gauge didn't move and and then the machine just stopped. I had seen before that sometimes the pressure was raised, but no espresso came out. So I assumed I grinded to fine or compressed the coffee to hard. But now, the machine didn't even try.

When I tried without the portafilter or with an empty one, water did came out. So I assumed the pump was fine. I tried backflushing, but that had the same result as when trying to make my espresso; it just quit. Man the Google!

This forum post where someone had the same, or at least a very similar, issue came up relatively quickly (I'm not good friends with search engines). The issue seemed to be a broken solenoid valve. This information led me to the two Youtube videos below. In the first he, R Brown, explains how the solenoid valve works and how to diagnose and clean them. In the second video he shows how to open up a Breville Barista Express and how to replace the solenoid block assembly.

Getting the solenoids out

I find opening up modern machines quite annoying. Everything is placed tightly together and often parts are "clipped" together instead of screwed. I hate that, because these clips can easily break and some screws are in hard to reach places. Often you cannot get your fingers in to catch of guide the screw and when they fall they are easily lost.

Anyway, the second video shows how to open your machine, so I'm not going to repeat it here. However, with the Solis I have there are one or two differences (this might also be with a newer revision Breville/Sage, I don't know).

At 1:55 in the video he shows three screws below the water tank. In his video they are all accessible from the top. In my case the two screws to the sides are mounted from the bottom. See pictures below.

To remove the back panel, in the new revision (or Solis only) two screws are now in the bottom.

Then around 3:05 in the video he says the back comes of with two clips on each side. In my case there are indeed two clips for the top 2/3's of the back, but also one in the bottom. You can unclip that with a screwdriver from the bottom of the machine or by pushing the bottom from the sides in, somewhere near my thumb in the image below.

Press somewhere around here to unhook the bottom clip to release the back panel.

Diagnosing and cleaning

Before I took the solenoid block out of the machine I first measured the resistance. In the previously mentioned forum post someone said this "should read 500 - 600 ohms" or "the [...] resistance for 230-240 VAC should be about 2x that of one for 110-120VAC". I measured ~2200-2400 ohms, which is around 4x the initially mentioned resistance. I have no idea what that means, is it good or bad? I decided this meant "good" as both solenoids had the same resistance.

I had already looked up the part with my "regular" parts dealer, who indeed sells the solenoid assembly, but the price was very discouraging: €142.60. Damn, the secondhand bargain ended up becoming pricy. I decided to go with the cleaning route first. See if that would alleviate the problem.

In the first video, R Brown disassembled the solenoid from the valve and shows what probably happens when the valve goes bad. Residue builds (scale) up and the valve gets stuck. No matter how hard the solenoid pushes or pulls, the valve won't open and no pressure gets to the grouphead. Obviously my valves look different. They are made of plastic instead of brass and as I don't have proper tooling I couldn't get the clamp of.

My solenoid block assembly with plastic piping and valves.

I disassembled the solenoids (with the valves) from the bracket and then removed the T-piece and elbow-piece. I carefully took out the red o-rings and put them apart with the clips and screws. I then took the yellowish top piece of and placed it with the bend and T in a water-vinager solution to descale. I then used a small rubber band to keep the solenoids together, so they could be placed on their valves in the solution as well, without tumbling over. I don't want vinegar or water in the solenoids, which is probably impossible, but I also didn't want to damage the tabs.

After a few hours I tried to clean the insides with a cotton swab. Nothing really came out. I decided to leave them to descale overnight and the next day repeated the cotton swab treatment. After drying them externally and tapping out some water, I reassembled the solenoid block (thank goodness I made a picture before), put it back in the machine and reconnected the wiring.

And...

It works!

I first flushed some water through the system without the portafilter installed. I then tried with portafilter and then tried a backflush. I got sustained pressure! Let's make some espresso. I started cautiously with a relatively coarse grind. The pressure on the gauge was lower than I was used to, but the taste was great.

Then I tried my usual recipe, with a much finer grind and again, the needle didn't go up as far as I expected. Before it was always at the edge of the "espresso range", but mostly even above. Now it peaked at 3/4 of the range. Again, nice espresso, although a little sour (I'm still fine tuning this months surprise "discover" coffee).

Today I again used the same grind size, but increased the amount of water. Again the pressure was in the 3/4 range and the espresso very drinkable.

With that, I think my problem is solved. The valves seemed to be "scaled up". So I think I'll run a full descaling routine soon, which takes some time, but way less than replacing parts. It is also much cheaper.

I hope this helps someone out there who runs into the same or a similar issue with one of these machines. Thanks to R Brown for his videos and the people on the home-barista.com forum.

Some sources: