Did I ruin the heating element?

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by CopperAZ »

I've been lurking for a while but decided to join and hopefully get some feedback. I took on a cleanup job for fun and hopefully good shots eventually, for an older Laranzato single/auto machine which I understand is the same as a Promac Club ME-1. It has a very large boiler and the machine seems very sturdy and weighs in the 50-70 lb range I'd guess.

Anyway I opened up the boiler to clean and the heating element was black. I'm not sure if this means that it was burnt at some point but the boiler was full of water and the boiler was a dark gray inside with some scale build up at the water line high up in the boiler. I made a citric descale and after a couple of hours the heater was still black and scaley and I did see some pink in a small area in the boiler and in the area that was above what was previously the water line it had been sitting at. (I'm told it sat like this unused for 2 years).

I did a second descale with the citric and used a higher concentration. After this I saw a lot more pink and some scale fell away as I washed it out and used a nylon brush inside. But most of the boiler was still dark gray and the nylon would not scrap any of the scale and I did not want to use a wire brush. The heater was no longer black and the tube running the middle had patches of pink. So I rinsed everything then started a vinegar/water bath at about 30% vinegar to filtered water. NOW here is where I had a freakout moment.

After opening this up again, the heating element looks like this:

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Randy G.

#2: Post by Randy G. »

Unless you used a very hot in temperature solution in a high concentrate and left the element in for days, whatever damage is found would have likely happened before you received it. It appears as if it is a stainless steel tube which was plated with copper, but that would be pretty crazy to do I would think.
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CopperAZ (original poster)

#3: Post by CopperAZ (original poster) »

yes that is what it looked like to me as well. I thought that the citric acid may have eaten through the copper plating. I didn't know if copper plating was a normal thing. after reading a few threads on here about using citric acid after using the vinegar I then washed it and then soaked it in a mix of water and baking soda. I don't know what to do next or if using this boiler and heating element would be in any way dangerous either from toxic copper or otherwise. The boiler itself is still mostly dark gray. I ordered some Durgol which I thought to just soak the boiler to see if the remaining scale could be removed. Any idea what the black stuff is?

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BaristaBoy E61

#4: Post by BaristaBoy E61 »

Have you measured the resistance of the heating element to determine if it's still good?
So far I don't see that you have done anything to get yourself in trouble.
Our copper boilers look rather grey inside as well with no ill effects.
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CopperAZ (original poster)

#5: Post by CopperAZ (original poster) » replying to BaristaBoy E61 »

That is good to hear. I have not tested it. When I purchased it, it turned on. I had just planned to thoroughly clean it before testing it out. I'm learning on the job here... When I opened it up and the the boiler was full of 2 year old water and the heater was black and crusty I just wanted to clean it up. Then I read the thread about toxic levels of copper on a thread here, and my water turned blue, on the second try with citric, I got concerned. Then seeing what looked like copper plating being destroyed I thought I may have just ruined everything.


#6: Post by Sw1ssdude »

i am pretty sure your boiler is not plated, but solid copper. or brass (made from copper and zinc)... so i dont think you destroyed any copper plating.

copper plating a stainless steel boiler is like brass plating a golden ring... makes not too much sense...

copper is very reactive, and submersing it into acids can lead to various things happening. might be that your boiler was nickel plated. nickel is easily etched away with citric acid, if you soak it long enough. the plating was most likely meant to be decorative and nice on the outside, but in the plating process the inside gets plated as well. this is what now appeared under the limescale...

the black stuff is copper oxide (copper(II)-oxide, there is also a brownish copper(I)-oxide). it is quite toxic, but very inert, and not soluble in water.

Meaning: it just sits there, looking grim and menacing, but its not getting in your coffee, not even when heated up. and it protects the underlaying copper from oxidizing. you will find it in almost all copper boilers (just read some various restoration threads on HB...). But it is soluble in acid, like citric acid, and slowly, slowly it will vanish. you can speed up things with fine steel wool, but be aware that the rougher you leave the surface, the tougher any new buildup (scale, oxidation) will adhere... use gloves while scrubbing away copper oxide, to avoid too much skin contact.

if you dont want to lose the nickel on the outside, you can try padding the inside with soaked rags or paper towels, to descale/deoxidize only on the inside. it will be slower than submersing the whole boiler, but it will keep the sheen on the outside intact...

i'm a bit more concerned about what appears to be a crack in the top pipe on your first picture...
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#7: Post by Marcelnl »

are you perhaps seeing chrome peeling off a copper heating element or whatever the center large diameter pipe is)?
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BaristaBoy E61

#8: Post by BaristaBoy E61 »

CopperAZ wrote:That is good to hear... Then I read the thread about toxic levels of copper on a thread here, and my water turned blue, on the second try with citric, I got concerned.
Turning blue is good. Lots of scale remaining turns the water dark green.
Pics below are from the last 2-descalings, 1-½yrs apart. Green was from 1st round of purging, blue, much later rounds.

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#9: Post by Nunas »

Over cleaning copper boilers isn't a good idea. Once the true scale (usually white/grey/tan depending on your water's composition) from the hard water is gone, you're then removing copper oxide, which isn't scale. Copper (I) oxide is red, copper (II) oxide is black but goes green in the presence of other elements including air. The thing is, copper oxide I and II on copper is natural and actually protects the copper from further erosion. Think the Statue of Liberty or the copper roofs on old buildings. If you clean right down to bright copper, eventually, the surface copper in your boiler will turn to copper oxide.

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#10: Post by Nunas »

To test the element, a simple resistance test followed by a test to ground from each terminal will give you a rough idea. But, the only true test is to fill the boiler with water, plug it into a GFCI outlet, wait a while, then switch it on. Heaters either work or they don't. When they fail, they usually quit working. However, there's a failure mode where they still work but become dangerous due to water incursion. If the outer sheath becomes ruptured, water will enter and the GFCI will be tripped.