I was hoping to get some help troubleshooting this problem with my espresso machine.  It has been working wonderfully the past few months since I bought it used off of craigslist.  I immediately backflushed it with purocaf, and try to take good care of it.  I only make a few shots a day, so it's not under heavy use.  I try to backflush with water after I'm done using it each day, and every couple weeks use purocaf.  Up until now it been fine, now when I brew, it leaks water out of the backflush valve and into the drip tray, and can't keep the proper pressure to brew.

 

I have tried to search online, but can't find much.  I have a basic understanding that it's probably something with the 3 way valve, but not sure what or how to fix it.  The only thing I've tried is an "aggressive backflush", as there may be some gunk keeping it from working properly.  Now I'm not 100% sure what that is, but I just backflushed a few times with a bit more purocaf.  That has not worked (although my machine it now clean I can assure you!).  Any other ideas?  How can I actually take the valve out and inspect it?  Is that possible?  Any info would be great, thanks!!

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So, are there any volunteers who would like to receive this valve guide in the mail to take a shot at it?  If you want the challenge I will be more than happy to mail it to you and you can give it your best, but I just clamped this thing onto a bench vise and yanked/bumped the crap out of it, using my leg to add more leverage, and it is not budging.  I have conceded and am going to buy a new one.  Unless of course you want the deadly valve guide in your mailbox...

 

Thanks for all the help with everything else though, so close!

Got it!  You can ignore the last post if you wish!

 

It looked fairly clean inside, not much buildup.  So what else could be wrong if there is no blockage?  A bad spring?  Bad coil?  I'm not sure about the seals though, as in, where there should be seals and where there shouldn't be.  Any suggestions?

 

Just one more question - When you press the brew button, the nucleus blocks the water from going down the drain tube.  Is the seal where the nucleus blocks this water at the bottom of the nucleus (when installed in the machine)?  Because I think if anything this would be the seal that is failing, because everything else looks good.  What would be the best way to repair that seal if I needed to? 

Daniel Demers said:

Got it!  You can ignore the last post if you wish!

 

It looked fairly clean inside, not much buildup.  So what else could be wrong if there is no blockage?  A bad spring?  Bad coil?  I'm not sure about the seals though, as in, where there should be seals and where there shouldn't be.  Any suggestions?

 


Daniel Demers said:

Just one more question - When you press the brew button, the nucleus blocks
the water from going down the drain tube.  Is the seal where the nucleus
blocks this water at the bottom of the nucleus (when installed in the
machine)? <snip>

 

Yes.

 

Daniel Demers said:

...Because I think if anything this would be the seal that is failing, because everything else looks good...


That's what I suspect too.  You probably have an issue with either that red seal or its seat.

 

Daniel Demers said:

What would be the best way to repair that seal if I needed to? 

Not sure what that red sealing material is, but it is pretty tough.  When brand new it is perfectly clean and shiny.  Over time, minerals and crud can build up on it, creating a film or a little ring.  Sometimes a little nick or scratch will compromise it.  Same goes for the valve seat, which is machined into the metal valve body parts.

 

If your valve is leaking, something has compromised the seal.  The trick is figuring out what the problem is and seeing if it is something you can resolve without causing more damage.

 

If there's a crusty buildup on the seat, you might try carefully scraping it off.  I have a small screwdriver that has no sharp corners or edges that I use to scrape off crust.  Sometimes it works, sometimes it doesn't.  If there is a scratch or nick on it, it probably won't work.  If there is a crusty buildup on the seat, you might try soaking it in descale or Cafiza, then cleaning it with a q-tip, pencil eraser, or screwdriver.

 

If you don't see anything obviously wrong after a careful inspection, you might just try re-assembling it.  Sometimes just taking them apart, cleaning them, and reassembling does the trick.

 

It is very likely that you will have to replace this valve.  I only stock the entire valve assembly and always replace the entire thing, but it looks like Espresso Parts stocks the various pieces.  If you can find the correct valve guide to fit your coil, that'd probably be the way to go.  If there's something visibly wrong with the nucleus you might try just replacing that, though if there's a problem with one of the valve guide parts you won't have solved the problem.

 

Hope this helps.  Good luck and let us know how it goes.

After careful inspection, I found that the bottom of the nucleus had a small rubber piece in the middle of it that sealed the bottom of the valve, but it was no longer there, so there was a poor seal which caused leakage.  I couldn't really find a replacement for that tiny piece of rubber, so I tried cementing a piece on there myself and see what happened.  It ended up being more rubber cement than anything, and after it dried it actually worked for about 2 or 3 pulls, then it started leaking again. 

 

I decided to replace the nucleus in the end, and I was able to get that from espresso parts, so all will be well in the end.

 

Thanks for all the info Brady, I learned a lot with this little experiment, and I now know how the three way solenoid works!  Eventually I'll figure out the rest of the machine in detail.

 

I think I would only show my joy of learning about my machine on this forum, otherwise there's a chance someone would think I was a bit strange....So, thanks!



Chris said:

  I don't recall any reason that you'd have to disconnect the machine from it's water supply if it's plumbed.  IIRC, the valve is normally open, and will only close when you pull a shot, yeah?


It takes a big man to admit when he's wrong, and I'm feelin' pretty big at the moment. And very wrong.
While you may not need to disco any plumbing, shutting it off is a great idea. And if 'off' doesn't completely stop the flow of water, you're going to have water running down your elbows and dripping past the drip-tray and all over the front of your pants on it;s way to the floor. DAMHIK,IJK.
Well, Karma decided I'd better put my money where my mouth is, and I had a leaky left group this morning. I had to go buy a truck all day, so I got to play with it when I returned this evening.
Disco from the plumbing if you get the opportunity.
Mine turned out to be a weak spring. I disassembled, cleaned, and reassembled, way proud of myself for getting it to stop leaking. One pull, however, and it was back to it's old tricks. Not a drip...drip. drip.. either. Almost the equivalent of the flow on a great shot. Disassembled, and added some 'power' to the spring (as a temporary measure 'til I could replace it) by stretching it just a bit. Yep, I broke it. So I really over-stretched it and replaced it so that I could use the Right group til I got parts. I'm thinking I may just replace the spring if I can get one, or just the solenoid cylinder . I dunno, maybe just the whole thing. I'll let my expert repair technicians make the call.

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