EM6910 - pump issues...?
Hi All, starting to wonder if it's time to retire my 6910 :-(
Last year, I replaced the collar and seal, but it's never really been back on form to where I'd like it.
Recently, without changing my dosing technique, the puck started looking really wet. I've tried increasing the dose / pack, but it's still not great and still seems wet. One thing I've noticed is it takes a lot longer for the pressure to increase while brewing. Typically, the needle doesn't even move for 10-15 seconds, only reaching read zone towards the end.
Just tried a descale and also noticed when back-flushing, the pressure remains in the group head and isn't backing off into the drip tray...
Perhaps a few issues going on here, any advice...?
Thanks in advance..
Sounds like the 3 way solenoid valve is not functioning properly. It is there to vent pressure from the group after the shot has finished. The two symptoms you describe: 1) Wet puck and 2) No pressure relief after the shot, both indicate a faulty solenoid valve.
Pressure taking a long time to build could be that the solenoid is leaking pressure to the drip tray during extraction causing the delay for pressure to build. The valve itself may have scale/coffee residue or some other buildup on the plunger seal or solenoid body itself. They're pretty easy to remove and clean. I'd suggest giving that a go first.
The solenoid is pretty expensive part to buy new, most Sunbeam part dealers will charge around $100. If you're confident at repairing it yourselves you'll save money on labour costs.
It's pretty much a basic 3 way solenoid with 1/8" threads on the solenoid body and an 8mm nipple for the silicone tube to the drip tray. You can pick these up on alibaba and the like for $5-10 a piece if you can find the right seller. Just search for "3 way solenoid valve coffee" and you'll get some hits.
Thanks very much noidle22 - sounds very promising.
I replaced the collar and seal myself last year, so will likely give this a go too, although the collar replacement seems to be better documented! ;-)
Will let you know how I go.
Hmmm, I might take that back! Have removed all the panels and controls etc. Pondered what was what for a while. Worked out which one was the solenoid and pipes in question. Confirmed with the service manual that my thinking was correct... BUT, really not liking the look of removing the pipes!! Any tips on pipe work??
Originally Posted by Footleg
Might try some hard backwashing!!!
Ok, now I'm gonna take back the take back!!
Originally Posted by Footleg
Decided to man up and created a strategy to have a go. Removed the pipe ABOVE my target that was blocking my getting a spanner on the jobbie. Removed the s-pipe (item 20 on page 8 of service manual - "solenoid copper tube") and sure enough, it seemed to be blocked. Soaked it in some cleaner, blew it through, soaked it some more until it seemed to be flowing freely... Removing the pipe was tricky because there's not much room to rotate the spanner, so a lot of little turns and patience was required.
Then, time to put it all back together.
Hey presto - pressure climbing properly, backwash working and back to dry pucks with small imprint of screen too!!! Even seems like main seal is working better too, but likely just coincidence... Just hoping I haven't introduced any leaks from the pipes I removed - I did do a test before I fully re-assembled the unit and it looked dry in the pertinent spots.
Thank you thank you noidle22!
A little more life left in the old girl yet...
Congratulations Footleg - there's a lot of satisfaction in working something through to a success.
One point - with my EM6910 and now with my EM7000 I found the recommended level of dose is an overdose. If I saw a screen imprint I'd usually also have leak issues. Even the 5c coin test seems to be too high. I dose about 5mm below the rim in both SB double basket and 15g VST basket and that gives me pretty much 15g-16g in both.
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