ECM Technika IV Profi - E61 Restrictor = Cold Grouphead

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
Parkeralto
Posts: 13
Joined: 6 years ago

#1: Post by Parkeralto »

After ten years of loyal service from my single boiler Quick Mill Alexia I decided to upgrade to a HX ECM Technika IV Profi. This was in April 2018. Having researched the ups and downs of HX machines I was prepared to fuss a bit with flushing and temperature surfing. It is direct plumbed and fitted with one of Eric's group head thermometers. I was very pleased with ECM quality and after a short learning curve was pulling excellent shots, or I should say shot because a (for me) serious problem became apparent when attempting back to back shots. At idle the GH temp would read 198 to 200 on a warm day; flushing would spike to 210 then settle down and give me a shot starting at around 200, raising up to 204 then tapering off to 196 at the two oz cut off.

The problem was that group head temp would continue to drop down to 180s (reverse siphon?) Flushing more water made the problem worse and It would stubbornly require 5 to 8 min. to get back up to brewing temp. I tried cranking the pressure stat up with little improvement. My inquires to W.L.L. where I purchased the machine yielded "that is normal for this machine" which I found completely unacceptable.

I figured there must be a restrictor in there somewhere because the group head temp was running so much colder than the HX water but could find no information about it. Not wanting to dump the machine or start tearing it apart I just lived with it for half a year until finally, after getting some ideas from the kind folks here at Home Barista. I grabbed some wrenches and had at it. This is what I found:



The internal design of the Hx is different from other ECM HX machines referenced on the forum. There is no plastic tube at the top (outlet) side. Just a right angle pipe fitting. The inlet side has a small diameter, straight copper tube with about a 2" gap to the top fitting.

There is a restrictor; a 2.5mm orifice plug brazed into the fitting which threads into the top of the group head. It is not removable.


So here is where I made the mistake of changing more than one parameter at a time. I drilled out the restrictor from 2.5mm to 4mm.


Then I put a little bend in the inlet tube to (theoretically) allow more mixing of Hx water with cold. The results were quite gratifying. GH idle temp rose about 4 degrees to 204; a quick flush spiked to 210 then down to 202. Brew temps are more stable ranging from 202 at the start, rising to 205 then back down to 202. Best of all; given a leisurely pace of grind and tamp, I can do back to back shots. I am just not sure which change is having which effect.

I am sure the engineers at ECM had good reason to put that restrictor in but at least for me, and I live in a cool climate, they went too far.

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Jake_G
Team HB
Posts: 4293
Joined: 6 years ago

#2: Post by Jake_G »

Michael,

Welcome to HB and thank you for such a detailed and helpful first post! I have no doubt there are countless other folks out there with these "cold nose" E61 machines with built in thermosyphon restrictors. Excellent topics like this documenting both the problem and solution with data and pictures in a single post are rare gems. I know of a couple current owners of Profitec Pro 500 PID machines that would benefit greatly by following your lead. I've no doubt that your contribution here will help give someone who has been similarly frustrated with the performance of their machine the courage they need to crack it open and fix it. Nice work.

Cheers!

- Jake
LMWDP #704

Bluenoser
Posts: 1433
Joined: 6 years ago

#3: Post by Bluenoser »

Hi Michael;

Thanks for the great post. I have a Profitec Pro 500 PID that was purchased in Canada about June, 2018 and appears to suffer from some of the same phenomena. My group drops 5 degrees after each shot and takes about 10 minutes to fully recover. I can pull 2 shots quickly, but after 3, the idle temp of the group really dips below 190 and here is where it takes 10-15 minutes to recover. I am guessing we have very similar designs as ECM and Profitec are virtually the same company from my understanding. However, mine is quite usable for 2 shots in a row and never drops as low as yours. (At least not yet)

I am unsure what you meant by "here is where I changed more than one variable". Did you run into some issue? How did you enlarge the opening? Were you simply able to redrill it? It looks like there might be a new 'something' added in the 'after' picture. And why would a bend in the pipe allow more water exchange. I am pretty new to these designs and maybe I missed something in the TS loop.

I wish they had designed the restriction to be more easily replaced or changed.

I don't think Germany is any warmer than Northern California so no excuse for bad thermal design.

Did you notice any scale when you took off the restriction? When I called IDC in Canada they thought my issue could be scale. But with a machine only a few months old, I don't know how scale would get in there. (I use very good water). And I got the same type of answer as you.. I was told that it is not unusual in an HX design for the brew water to vary 10F. From everything I read here and even by WholeLLove's vids on the PRO500PID brew water only varied 1degF. Disappointing when you have an issue that they didn't look into it more.

I think that most owners do not even know they have an issue as without an external thermometer how does one know the brew water is this low?