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PostPosted: Mon Feb 11, 2013 11:25 am
by GreenBean
simonp wrote:OK, now I'm very confused... whilst I was running the descaling solution through in several lots and 10 minute soaks I was getting flash billing out of the group as I ran each lot through. Now it is flushed and back running as normal it is back to coming out cooler with no flashing. The outside of the group only measures just above 70C. Not sure where to go with this now...

If the group is significantly cooler than normal whilst the boiler pressure (and, therefore, temperature) is normal then either there is a restriction in the thermosyphon flow or scale on the walls of the heat exchanger is reducing it's efficiency. If you are lucky it may be a piece of scale partially blocking the thermosyphon pipework which can be dislodged. Otherwise a more thorough descale of the boiler/heat exchanger/thermosyphon pipework would seem to be necessary. :(

PostPosted: Mon Feb 11, 2013 11:39 am
by simonp
I took the top of the group apart again and found loads more scale flakes had come through, so it seems you are right. I was briefly getting a good thermosyphon going whlst the descaler was in there but I guess flushing shifted bits and slowed it again. No option but a complete strip down. Trouble is getting any parts I may need if I can't clear them as few people in the UK do Isomac parts apart from the main consumables like Heating elements, lamps etc. I'm hoping a generic E61 seal kit will fit, but if (as seems often) I have issues with geting the brew plunger etc apart the bits could be hard to find.

I guess I need to hunt down some hydrochloric acid (or something like it) now, I think the scale will be beyong the usual citric acid!

I guess the prss pot and Chemex will be getting a lot of use!

PostPosted: Mon Feb 11, 2013 12:09 pm
by GreenBean
It is not unusual for descaling to dislodge scale that is not then completely dissolved. This scale is likely to collect around the gicleur filter screen. This is why I said in a previous post:
GreenBean wrote:Don't forget to check the gicleur/jet/flow restrictor and it's associated filter screen after the descale to ensure they are not clogged.

You could try flushing it through a few more times and cleaning the filter screen as necessary to get as much out as possible. This may allow you to put off the thorough descale for some time.

simonp wrote:....I guess I need to hunt down some hydrochloric acid (or something like it) now, I think the scale will be beyong the usual citric acid! ...

Citric acid can cope with any amount of scale although it may take some time and a number of attempts to remove all the scale. It is also much safer than other acids.

PostPosted: Mon Feb 11, 2013 2:05 pm
by simonp
GreenBean wrote:It is not unusual for descaling to dislodge scale that is not then completely dissolved. This scale is likely to collect around the gicleur filter screen. This is why I said in a previous post:
GreenBean wrote:Don't forget to check the gicleur/jet/flow restrictor and it's associated filter screen after the descale to ensure they are not clogged.

You could try flushing it through a few more times and cleaning the filter screen as necessary to get as much out as possible. This may allow you to put off the thorough descale for some time.

simonp wrote:....I guess I need to hunt down some hydrochloric acid (or something like it) now, I think the scale will be beyong the usual citric acid! ...

Citric acid can cope with any amount of scale although it may take some time and a number of attempts to remove all the scale. It is also much safer than other acids.


Well, the plan is I've ordered a "generic" E61 seal kit (let's hop that fits!), so I will descale the inside of the group on its own and then fit the new seals. I'll try some more flushing, and possibly more de-scaler (maybe longer and stronger). I might pop the pipes off the HX connection on the boiler and have a look anyway and if they look bad I will do a complete strip and soak.

I guess my issue with the citric acid and the "mushroom" was that there was so much scale it neutralised the acid before it removed all the scale. Citric acid may cope with any ammount of scale given enough time, but can my wife cope with bowls full of acid lying aorund for that ammount of time? :lol:

PostPosted: Mon Feb 11, 2013 3:15 pm
by bruceb
Boil the parts in citric acid. That works almost as quickly as hydrochloric acid on most scale. I use an old immersion heater in a tub of the stuff.

PostPosted: Mon Feb 11, 2013 4:10 pm
by lsjms
+1
I have become convinced over the last few years and several machine rebuilds, that over aggressive hydrochloric acid bathing produces machines that just 'ain't right' Even if the parts are all stripped so there is no mixed metals in contact with each other, as opposed to flushing through- with acid reaching seals and gaskets, something changes. Leaks and minor faults are more likely and service needs seem higher.

Totally IMO, I might be dreaming but nothing but textbook solutions of hot citric for me now, if it takes time, so be it. Years of abuse deserve a week in the dip.

You should be able to get any parts for that machine pretty easily- lots are same as the other e-61's. If you are really stuck Janksolid on this forum can find anything. Send him a PM.
What's a brew plunger?

PostPosted: Mon Feb 11, 2013 4:27 pm
by simonp
lsjms wrote: You should be able to get any parts for that machine pretty easily- lots are same as the other e-61's. If you are really stuck Janksolid on this forum can find anything. Send him a PM.
What's a brew plunger?


Everyone I have contacted so far tells me there are as many differences in the E61 as there are similarities, different legnth of internals etc. Though it looks like the seals at least are generally the same.

Brew plunger, well it is my description for the shaft and seal that gets lifteted when the lever goes into the brewing position to open the brew valve which lets water into the path to the head, showerscreen etc.

I'll stick with the citric acid then, just increase my patience!

PostPosted: Mon Feb 11, 2013 9:39 pm
by bruceb
There is only one "real" E61 and those are the ones that were on the original E61 machines. You will need to get the parts from an Isomac dealer and they will need to be the parts for your machine.
Professional espresso repairmen use hydrochloric acid, but they are working on commercial machines with big, thick copper and brass tubing and connectors, boilers, etc. You may get etching on poorer quality materials and that may cause leakage. I managed to descale a 10 L boiler on a big, 2-group machine that had over 10 lbs of scale on it using citric acid. It took about 5 kg of the stuff, however.

PostPosted: Mon Feb 18, 2013 12:09 am
by simonp
bruceb wrote:There is only one "real" E61 and those are the ones that were on the original E61 machines. You will need to get the parts from an Isomac dealer and they will need to be the parts for your machine.


As it happens the "generic" brass plungers/valve parts were correct for the Isomac E61, hand to to know for the future.

PostPosted: Mon Feb 18, 2013 12:14 am
by simonp
Well, after I solved my machine issues (see my separate thread on the Rituale rebuild), it seems my laziness had not been the major cause of my poor espresso. Granted I think the accurate weighing of dose and shot helps a lot, i think the fact that the machine was just brewing WAY too cold was the major factor. However it still come down to complacency on my part in letting the machine deteriorate and then not twigging for so long.

I am now pulling some excellent shots, with consistency, but the extra attention to preparation means I can predict the effect changes in dose and grind will have on the shot.

The moral of the story is to stay vigilant, and keep up with technique improvements in the world of coffee!

PostPosted: Mon Feb 18, 2013 8:36 am
by GreenBean
simonp wrote:... I am now pulling some excellent shots, with consistency, but the extra attention to preparation means I can predict the effect changes in dose and grind will have on the shot....

Great news, congratulations Simon. :D

PostPosted: Mon Feb 18, 2013 11:10 am
by bruceb
Good to hear that you got things sorted, Simon. I have had a salt-regenerated water softener on my machine for the last 6 years and have been able to avoid the scale problem, thank goodness.