Judging from this scale on E61 mushroom, does the boiler/HX need descaling?

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.
robc
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#1: Post by robc »



I am hoping someone can advise me. I have an Expobar Office Lever that is just over one year old. I am wondering if I should descale it for the first time. While attempting to troubleshoot an issue with thermosyphon stalling, I recently opened up the grouphead and was surprised to find scaling on the mushroom. I have always used RO water (since water here in AZ is extremely hard). My RO water is currently measuring at 28 TDS. If this scaling is on the mushroom, is it fair to assume it is in the HX and boiler, etc? Any suggestions would be greatly appreciated.

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cannonfodder
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#2: Post by cannonfodder »

I would not worry about it. That is very light scale, almost none actually. At that rate you could descale around every 3 years and never have more than light scale in the machine.
Dave Stephens

robc (original poster)
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#3: Post by robc (original poster) »

Thank you Dave! Would it be worthwhile to descale the machine every year or two as preventative maintenance? I am not sure what approach to take since I've read conflicting theories and instructions. If an occasional descale is recommended, would you suggest running the descaling solution from the water reservoir and disconnecting the boiler level probe? Thanks again!

XCman
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#4: Post by XCman »

Last year I had thermal-stall problems. When I checked the mushroom it was clean. Much cleaner then yours. After hours of trouble shooting I finally descaled and was back in action.
Descaling is cheap and easy. And if that doesn't fix it at least you've eliminated one possibility and have a
clean boiler and HX.

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VeniaCoffee
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#5: Post by VeniaCoffee »

Rob,

It is very tough to tell by the photo, but, what I see is not scale but corrosion of the metal. Learning you are on RO and running at 28TDS would also lead me to believe it is indeed corrosion. In general, 28TDS is very low. Many commercial espresso machine manufacturers recommend a TDS in the 125-150 range. This recommendation has several purposes, one of which is to prevent both scale and corrosion.

An easy test would be to place the mushroom in a descaling solution to see if the visible "scale" is reduced/eliminated or not. If it does come off in a descaling solution, give the machine a descale to see if that helps with the thermosyphon stall. It it is corrosion and you are experiencing a stall, my guess would be the gicleur (a small inline aperture that limits flow rate) has corroded a bit.

TDS is a small part of good water, but I would recommend bypassing a bit more water on your RO system to get your TDS more in the recommended range. You can check out a talk posted on our blog that addresses water in detail. While the whole video is excellent, start watching from around the 14 minute mark. http://www.veniacoffee.com/shop/blog/20 ... in-coffee/

Keith
I am hoping someone can advise me. I have an Expobar Office Lever that is just over one year old. I am wondering if I should descale it for the first time. While attempting to troubleshoot an issue with thermosyphon stalling, I recently opened up the grouphead and was surprised to find scaling on the mushroom. I have always used RO water (since water here in AZ is extremely hard). My RO water is currently measuring at 28 TDS. If this scaling is on the mushroom, is it fair to assume it is in the HX and boiler, etc? Any suggestions would be greatly appreciated.

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Randy G.
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#6: Post by Randy G. »

I agree with Keith. My first thought was also that this is corrosion. Nothing to be worried about, but something to be addressed. You could add a post-RO calcite filter to add minerals or if there is a bypass for the RO do as Keith mentioned and turn it up a bit.

There are things in water that show as TDS which are not scaling. Also, it takes GH + KH together to create scale, and that is why the Aquarium Pharmaceuticals GH+GH GH+KH test kit is so handy. It gives you a lot more info than just TDS.

A thermosyphon stall could be a clogged or corroded gicleur screen, but could also be caused by a slow leak or short user flushes. The leak could possibly not show if it is through the group as the water could be vaporizing and not forming droplets. If you use the search function here on HB there are a number of articles that deal with it.

If the chrome is flaking on the mushroom, remove the seals and use a fine wire wheel brush to remove the flaking, or even all the chrome. Otherwise, maybe just a scotchbrite pad or equivalent to clean it up so that subsequent inspections will revel more useful data.
EspressoMyEspresso.com - 2000-2023 - a good run, its time is done

jonr
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#7: Post by jonr »

Might be worth checking the pH of your water.

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homeburrero
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#8: Post by homeburrero »

Randy G. wrote:that is why the Aquarium Pharmaceuticals GH+GH test kit is so handy. It gives you a lot more info than just TDS.
I'm with Randy on this. I think he means GH+KH. That test kit is cheap, dirt simple to use, and since it measures alkalinity you don't need to measure the pH*. If you have low alkalinity then that might be a source of corrosion (if that is what's causing those brown spots on your mushroom.) Consult the Jim Schulman's Insanely Long Water FAQ - has tables relating alkalinity to pH (below 50mg/L is where the pH starts to shift to the acidic side) and some handy tables for scaling rates at given hardness (GH) and alkalinity (KH) values.
VeniaCoffee wrote:It it is corrosion and you are experiencing a stall, my guess would be the gicleur (a small inline aperture that limits flow rate) has corroded a bit.
Randy G. wrote:A Thermosyphon stall could be a clogged or corroded gicleur screen ...
Are you guys sure about that? My understanding of the e61 is that the water doesn't go through the gicleur until you open the brew valve - have a hard time seing how it would cause a stall. Clogged thermosyphon restrictor, yes that could cause a stall.



*(added comment) For natural waters at equilibrium with air you can pretty much predict pH from the alkalinity. Alkalinity measurement is a process of adding acid and seeing how much it takes to get the pH down to 4.3. However, for treated waters it's possible to have a lower pH than predicted by the alkalinity measure. One common case of this is water that has gone through a weak acid cation exchange resin (some Brita and Claris filters have these resins.)
Pat
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Randy G.
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#9: Post by Randy G. »

APOLOGY: This is what I deserve for typing pissed off (unrelated to HB) at 1:00 AM!

1 - I corrected the GH+KH mistype in my post above.
2 -
homeburrero wrote:My understanding of the e61 is that the water doesn't go through the gicleur until you open the brew valve ...
That is absolutely correct. And a big DUH award to me! I should have checked that (refer to above apology).
For a proof-read, thorough explanation of the E-61 group, download the Vibiemme DD manual I wrote for 1st-Line.com and Espressocare.com as it has the group diagrammed in all its stages (on pages 5-8):
http://www.espressocare.com/PDF-Files/V ... nal_1c.pdf

Be sure to look at pg. 43 as well since it has a high giggle factor for us HB'ers..
EspressoMyEspresso.com - 2000-2023 - a good run, its time is done

robc (original poster)
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#10: Post by robc (original poster) »

Thank you all for your input! I will work on getting the water balancing issues corrected.

I did not consider that it could be corrosion instead of scale. I soaked the mushroom in vinegar for approx 20 minutes and was then able to wipe it clean.

I am going to try running a descaling solution through the machine to see if that corrects the stalling issue. I read once in an Isomac Tea instruction manual to use vinegar. I have also read DO NOT use vinegar. Do you guys have an opinion? It seems for every DO on the internet, there is a DO NOT. :?

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