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The Coffeetime E61 servicing information was invaluable to me. Thanks very much.

I just rebuilt my E61 group head following these instructions . Here are some observations pertaining to other comments:
1. I did not remove the E61 from the machine and had no trouble disassembling it. However replacing the bottom part requires a lot of upward force on the spring before the part can be screwed in.

2. Regarding the chrome flakes: the chrome plated brass(or copper?) part inside the top of the brew head on my machine(Quick Mill) was corroded with chrome flaking off, so I cleaned it up with a steel wire brush. This a good time to just flush the whole thing out since the top and bottom are both off.

3. A 7mm box end wrench(spanner for UK people) works great for holding the triangular shafts.

4. To reduce the possibility of breaking the little brass plungers when unscrewing them to change the seals, try dipping the parts in a cup of boiling water for about 30 seconds before trying to unscrew.

I made an account just to thank you for this easy to follow tutorial. It was so helpful!!!

THANKS by tdifraiatdifraia, 06 Feb 2014 14:58

Thanks Mole – this is an excellent and valuable article.

I’m currently tweaking my Ascaso Steel UNO with PID; same Gicar controller, and default has severe overshoot (initial settings are PID = 2.5, 0, 4.0; yes, that’s a “0” for I) – as with the Izzo, it’s optimizing rise time at the expense of settling time, and being conservative with D and I to avoid stability problems.

I’ll give more details when I’ve worked it out (to start, P = 1.2 is a major improvement); my initial thoughts on tuning are:

  • I can be tuned independently, as it’s most significant for steady-state error
  • P and D are interdependent, and primarily for “recovery from shot/flush/cold”; they also interact with I

My initial suggested tuning routine is:

  • First adjust P so it’s roughly correct (1.2–1.6, say)
  • Then adjust I so it’s .01 below causing steady-state overshoot – these yields maximal stability, and is tunable independently of others, b/c I is only factor when at target.
    • May want I lower if pull many shots in sequence, as otherwise may overheat some.
  • Then adjust D so get fast recovery from common uses (pulling shot, small or large flush) – i.e., fast w/o overshoot
  • Then fine-tune P, to improve recovery – both from cold and post-shot – adjusting D as you go.
    • Mostly trading off P and D (increase one, decrease the other by some multiple, so get fast enough heating w/o overshoot).
    • (For fixed I*), for any value of P, there is an optimal D, and among these optimal (P,D), there is a best (P*,D*).

Thanks again for your careful and thorough study!

Thank you! (and thoughts) by nbarthnbarth, 17 Mar 2010 05:18

Try www.teknomat.co.uk. They got me a part I needed for an Expobar machine and were very helpful and efficient and deal with most makes I believe.

Just a quick query to see if anyone out there has some experience in sourcing spares for Isomac? I have the milleniium and would like to change the valve seat/seal on the steam valve, as the wand has started to drip ever so slightly. In addition, the steam wand rotary joint needs to have the 'o' ring changed as I get a slight weep from that joint too. Neither of these faults are major, but I've started with the usual route of spares supply - Bella Barista, they don't have the spares I need. Another Coffee didn't have the spares either, any ideas? I have considered swapping over the water valve with the steam wand valve, but I'm just transferring the fault from one place to another and not really gaining anything. Surely there's nothing special about these valves and generic spares will probably fit, but where do I start for sourcing?
Steve

Can I start off by thanking all who contributed to shedding light on this subject, Dave C needs a special mention in view of his particular attention to detail and comprehensive response. After cleaning off the remaining chrome from the spring housing that comprises part of the top valve on the group, I backflushed a further 4 times and passed about 4 tanks of clean water through the machine ( filtered -very soft water area! ). After each Backflush and full tank clean water flush through, I'd draw off about 8 oz of water into a pyrex glass and hold it up to the light and see the silver flecks sparkling back at me. As this process proceeded the flecks grew smaller and the only way to see them then was to pass the water through a paper filter and use a 10x magnifier, they were still there. Call me fussy, but I didn't want to see chrome flakes. By the end of the fourth backflush and fourth tank of water it came clean. I know the coffee puck would have filtered out most of it, unless I experienced some bad channelling tamps, I just didn't want heavy metal in my system! I recommend anyone descaling for the first time to take the top valve assembly off after the descale process and clean up the offending component with scotchbrite pad or similar. That way whoever does it will save themselves a lot of trouble with chrome flakes. The descale thing for me was one of those issues, shall I or shan't I. I know that a good indicator of scale is your kettle and mine ( glass ) didn't show very much at all after many years, but I thought o.k it won't do any harm to give the machine a clean up!!
Coffeetime is an amazing resource, without it I wouldn't have had the confidence to go ahead and try to tackle the E61 strip down, I look forward to reading the future article on pre-infusion.

E61 group servicing by ChrisnSteve NelsonChrisnSteve Nelson, 18 Jun 2009 19:49
Paul LPaul L 18 Jun 2009 11:20
in discussion Hidden / Per page discussions » E61 Group Servicing

With prevention better than cure and water being the reason a descale is required in the first place, the articles on the wiki on water are worth you looking at if you have not already done so. These arose from discussions Dave led and steps he was already taking.

by Paul LPaul L, 18 Jun 2009 11:20

Chrome flakes can only come from the area bordered by the red dotted line in this article.
http://coffeetime.wikidot.com/the-mystery-of-the-e61-group-mushroom

The article below explains the metal flakes, although I should update it, because yes you can get some chrome flakes…but they are not as profuse and of course are not a sign of a lack of lubrication (yet another Wiki article on lubrication http://coffeetime.wikidot.com/e61-lubrication )
http://coffeetime.wikidot.com/metal-flakes-after-descaling

The group can be disassembled in situ on most machines….no problem, but you will need the type of adjustable spanner shown in the article to ensure sufficient clearance to do so.

I need to do an article about pre-infusion, because there is a common misconception that there is some "middle position of the lever where "pre infusion" takes place….there is not. Pre infusion is a mechanical process utilising a chamber and a sprung valve (set to operate at around 3-4 bar), this ensures a period of lower pressure, prior to the ramp up to 9 bar or whatever the pump is set to. Just lift the lever all the way and let the E61 group do the work.

Re: Disassembling E61 in-situ by DaveCDaveC, 18 Jun 2009 10:49

Its not an issue the flecks , back flush with puly caffe or continue a few more flushes , it will eventually clear after a few more rinses . It tends to be brass rubbings from the lever not chrome . When I 1st descaled a few years ago it looked awful. Since then it does not appear much . I assume its the 1st descale ?

by michael knowlesmichael knowles, 18 Jun 2009 09:50

Dave,
Any thoughts on whether this disassembley process can be done with the E61 still in position. Following my first descaling with citric acid, my brew water has been contaminated with chrome flakes, no matter how much I backflushed or flushed with clean water, they were ever present. I have taken the top valve off in -situ in order to clean the chrome coating that was peeling off the spring housing component within the top valve assembley. Any thoughts on how easy it would be to reassemble the bottom valve in situ? Taking it apart will be easy, aligning all the components whilst working against gravity puts me off trying. What do you think? I'm wondering if there are any components in the lower valve assembley that may be leaching chrome flakes? I know this isn't a direct comment on the article but it is E61 related, it's about the preinfusion valve operation. Should the brew head pre-infuse with the lever just put in the mid position? My valve has to be 'teased' just past the mid position: just on the edge of the pump starting before it pre-infuses. Is this normal? Another reason maybe why I think I need to disassemble the bottom valve.