I gave my Son an Oscar and he has been using it 3 or 4 months.

He tried backflushing but nothing is coming out in the bottom tray

Also the PF gets jammed after trying the backflush ?

what can I advise him ?? It works fine otherwise

Seems as if the 3-way is jammed and not venting the pressure in the group after turning of the pump. He might wanna take it apart and soak it in cleaner to get it working again, and then back-flush a bit more often (if it's grime that got it stuck, might be swarf from the manufacturing process or a faulty valve as well)

the 3-way ??

Is it complicated to do ?

See What is a three way solenoid valve? It explains what it does and links to more details.

Gaining access to the three-way solenoid might prove to be the most troublesome. The rest is EASY.



With the machine unplugged, remove the retaining nut & washers, and slide the solenoid off.



Using a 7/8" or maybe 22 mm wrench, unscrew the valve housing (pc 2 above). The valve itself (pc 1 above) floats inside piece 2. Give pieces 1 and 2 a soak in Jo-Glo or equal for about 15 minutes. Rinse off and then soak in white vinegar for about an hour. Rinse off, reassemble and you should be "good-to-go".

There is no need to remove the valve seat housing from the grouphead unless you see evidence of scale, etc. In that case, have two new o-rings handy (OR 105) although you may not NECESSARILY need to use them.

Before backflushing he should clean the group screen and dispersion screen see last post in this thread. It puzzles me that you say it works without problems otherwise? If the solenoid is jammed you would also expect 'portafilter sneeze' after each shot because pressure release from the group is not working.

edit: here are some pictures　and here you can find the parts list.

Good luck!

He clarified that there is a "little" bit that comes out when he backflushes.

He did remark that if he did several backflushes in a row, the portafilter becomes jammed in place do to the pressure buildup.

I will send him these diagrams, but he is no mechanic and doesn't have tools. He's an Art Student at College

I guess its time to learn a little mechanics

He only needs a flat screwdriver or a coin, a toothpick and an old toothbrush for cleaning the screen and diffuser disk. No need to open the case.

One step at a time

misterdoggy wrote:He clarified that there is a "little" bit that comes out when he backflushes.

He did remark that if he did several backflushes in a row, the portafilter becomes jammed in place do to the pressure buildup.

I will send him these diagrams, but he is no mechanic and doesn't have tools. He's an Art Student at College

I guess its time to learn a little mechanics

Now, if I remember correctly the espresso machine cleaners doesn't dissolve scale. So if the flow from the 3-way valve doesn't improve after several flushes, then he has scale in the valve that keeps it from doing it's job properly. He needs to clean that valve somehow, I would disassemble it.

BTW, is it possible to backflush with citric acid to remove scale in the group and 3-way valve?

Since the machine is only a few months old and he uses only brita water (30ppm) I sincerely doubt that its scale buildup at so early a point.

More likely grime or grinds or coffee film due to the fact he only back-washed once a month.

If I remember right on this machine its not that easy to take off the screen as it is held in place with the gasket which can be a real pain to pull off especially after its hardened.