Re: ECM Technika III OPV
Thanks Starbugs. I think it is a somewhat different OPV as I could get
to the inner screw immediately (took some effort to get it moving
initially, but easy after that). And only about one full rotation for a
similar amount of adjustment to yours. Nonetheless Im not happy
with the hysteresis, Ill get the OPV checked when I have the machine
serviced. All is working well at the moment though, thats the main thing.
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Re: ECM Technika III OPV
Hi Hazbean
The pump pressure reduction was achieved quite easily by turning the inner screw three full rotations (CCW ), verified with the blind filter after each rotation.
The tricky bits are the untightening and tightening of the inner screw with two shifters in a tight spot - that took me quite a while.
I am not seeing any hysteresis and the repeatability is good. Maybe it is due to different type of OPV, I am not sure.
Thanks Rivera. The link settles my question once and for all.
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Re: ECM Technika III OPV
Starbugs: missed your followup due to being away. I see your comment
"It was not as straight forward as I had imagined ..." -- just curious
as to why it wasnt. In my case, even with sound advice from the
helpful people at the Isomac workshop, I found it slightly tricky to
figure out how much to rotate it: I had to iterate backwards and
forwards a few times, and noticed a fair bit of hysteresis in the
adjustment.
Rivera: interesting link, thanks.
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Re: ECM Technika III OPV
Ive been doing a lot of reading on this as I too need to adjust the OPV on my machine. I came across this post by chang00 on HB that provided clear information on the matter:Originally posted by 63676E6D63617C7C080 link=1249637081/5#5 date=1249695898My apoligies for linking to the wrong machine, i thought as they were the same manufacturer they would use the same opv.
Can someone explain to me why when 9 bar is the accepted norm or ideal brew pressure most machines seem to be supplied running at 12-14 bar? I realise the on board guages are not always accurate and measure the pressure before the grouphead so often read 1 - 1.5 bar high.Surely if they were supplied running at 9 - 10 bar we wouldnt have all these threads asking about how to adjust the opv, and then the supplier saying oh no, dont do that - youll void the warranty
At risk of being ultra-geeky, this is an article which discusses the effect of brew pressure and espresso:
http://pubs.acs.org/doi/abs/10.1021/jf0206623
Specifically, at 11 atm, the concentrations of 2-methylbutanal, 3-methylbutanal, and 2-ethyl-3,5-dimethylpyrazine are higher. These compounds are generally responsible for bitterness and astringency.
At 7 and 9 atm, methanethiol and propanal concentrations are higher. At 9 atm, these compounds tend to be slightly higher compared with espresso prepared at 7 atm. Methanethiol is responsible for the "freshness" perception, and propanal is correlated with "fruitiness" generally.
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Re: ECM Technika III OPV
on some bezzera machines, it gets known as the godshot squeal.Originally posted by 6245504353445642310 link=1249637081/8#8 date=1250332063Occasionally the OPV will momentarily "scream" or "screech"
J
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Re: ECM Technika III OPV
Managed to adjust the OPV to 10.5 bar. It was not as straight forward as I had imagined and having to work in a very tight and confined space added to the challenge.
Nevertheless, it is well worth it and now I am getting thick and golden espresso syrup and could control the pour to 30 sec.
The taste of coffee is slightly mellow minus the "bitterness" for want of a better word resulted from high pressure brewing and over extraction.
Occasionally the OPV will momentarily "scream" or "screech" when the pump pressure hits 10.5 bar and I guess it is normal where the internal of the OPV has to oscillate at high frequency in order to regulate pressure.
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Re: ECM Technika III OPV
You might want to have a look at a post I made about OPV adjustment
a few months ago. Not the same machine, but the OPV is similar.
See http://coffeesnobs.com.au/YaBB.pl?num=1236582474
The machine pressure gauge reads about 10 with a blind filter.
Im very happy that I made the change. With brew pressure in the
range 13-14, I could adjust grind and dose to get a 25-30 sec pour, but not easily, and the
results at "correct" brew pressure are vastly preferable.
If you do it, would be interested to see a report ...
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Re: ECM Technika III OPV
Hi vicroamer
I think the dealer just powered up the machine to check all system go before despatch. I assume adjusting the OPV is not part of the purchase deal then again I might be wrong. I didnt ask.
Hi Renzo
That is nothing wrong with the machine. Nothing will and can go wrong with German made machine ;D. The group pressure, as I understand from a lot of experienced commentators, is about 1- 1.5 bar lower than the pump pressure.
I would be guided by the pump pressure gauge that comes with Technika III and set the OPV so that the gauge reads 10 - 10.5 bar to deliver 9 bar group pressure.
I agree with Kofekitt, if 9 bar pressure is the standard of espresso extraction why arent coffee machine manufacturers tweaking OPV at factory to that setting.
I pulled a number of shots at 14bar and they are pretty good just that the brew time is about 15 sec. My understanding is by reducing the brew pressure to about 9 bar, the brew time will increase - hopefully to 25 - 30 sec thus giving ample time for proper coffee exxtraction. Correct me please if my understanding is flawed.
BTW, thanks Kofekitt for the link. It is definitely helpful!
Thanks fellas.
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Re: ECM Technika III OPV
My apoligies for linking to the wrong machine, i thought as they were the same manufacturer they would use the same opv.
Can someone explain to me why when 9 bar is the accepted norm or ideal brew pressure most machines seem to be supplied running at 12-14 bar? I realise the on board guages are not always accurate and measure the pressure before the grouphead so often read 1 - 1.5 bar high.Surely if they were supplied running at 9 - 10 bar we wouldnt have all these threads asking about how to adjust the opv, and then the supplier saying oh no, dont do that - youll void the warranty
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Re: ECM Technika III OPV
Hi Starbugs,
This the German ECM, you will have to take all the side panes to get there, but unless you have group pressure gauge or Scase handle (http://www.espressoparts.com/EP_THERMOFILTER2) I would not recommended.
Is anything wrong with your machine?
Regards
Renzo
Di Bartoli Home Barista Centre
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Re: ECM Technika III OPV
Whoops, sorry, bad link.
Try this http://www.bellabarista.co.uk/pdf/ECMMechanikacloserlookv1.pdf
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Re: ECM Technika III OPV
Have you seen this review? It shows the opv location.
Click Here (www.bellabarista.co.uk)
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Re: ECM Technika III OPV
Something the dealer should have set for you, maybe they will adjust it for you.
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ECM Technika III OPV
Hi
I would like to find out how I can access the ECM Technika III OPV. Can it be accessed from the top or do I have to remove the side cover to get to it?
If it is the latter, how do you remove the side cover? :-?
Using a blind filter with the pump running, the pump pressure gauge shows 14bar and I want to set it to 10bar. I assume tweaking the OPV counter clockwise will reduce the OPV pressure.
Thanks.Tags: None
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