Reddish water from La Pavoni after fixing and cleaning

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
MT
Posts: 10
Joined: 9 years ago

#1: Post by MT »

Hi all

I own a 2005 La-Pavoni Europiccola Milenium for 7 years now. The first few years we lived in a place where the water are very hard, and I did a poor job cleaning the machine (shame on me). When we moved to the US I kept running the machine with a transformer, and started getting into the habit of descaling it (a friend of mine recommended "cleancaf", which I think was a bad idea). A couple of months ago the machine died altogether and I replaced the heating element (so no need for transformer), most of the seal in the group and the power switch. While the machine was open I got to take a good look at the inside of the boiler, and saw that some scale (on the groove right above the heating element) remained. After removing it I saw it caused some damage to the inside coating (nickel, I think?), so some copper was exposed.

Ever since that fix the water has been coming out reddish from the machine. It's much worse with tap water, Brita helps a bit and distilled helps a bit, but nothing solves the issue. Right now I'm changing water daily to prevent the water from being really red/brown, but I was wondering if anyone has experience with this issue and if there is a solution for it. Is it bronze disease? Do I need a new boiler (and if so, where can one find one?) Any help would be most welcome!

MT (original poster)
Posts: 10
Joined: 9 years ago

#2: Post by MT (original poster) »

Sorry, I forgot to mention that the base of the heating element also turned red. I took the machine apart and cleaned it once. That lasted for a few days but it turned red (rusty) again. Could that be the source of the redness in the water?

OldNuc
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Joined: 10 years ago

#3: Post by OldNuc »

What are you using for water?

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rpavlis
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#4: Post by rpavlis »

I purchased an 1978 La Pavoni from someone who had used sulphate hard water in it. It was badly scaled with calcium sulphate. Ordinary descaling solutions are useless for this, so I simply used pure distilled water. (There are things one can do, but this is the least violent to the machine and possibly those drinking espresso from it.) Because calcium sulphate is sparingly soluble the scale disappeared in a few weeks. When it finally was totally descaled, the water was reddish. If I were to drain it completely after each use it would be red the next time. Once when I was draining it I heard a rattling side inside and inspected it more closely than I had before. There was an M6x1.0 nut jammed into the coils. The scale apparently had insulated the nut from the copper coils of this machine until it was removed. When in contact with copper the nut quickly began corroding and this produced red iron oxide. With the machine upside down I pushed around on the nut until it fell out. After this there was no more reddish water.

Could something made of steel have gotten into the boiler?

I normally only use my "espresso water" which is 1 millimolar potassium bicarbonate. Potassium bicarbonate is used for several food uses. Its molecular weight is 100 g/mole. If one make a 10% solution by dissolving 10 grams of it in 100 mL of water, you can use this to make the 1 millimolar solution. There is nothing magical about having calcium in brew water, because there is more Ca in the beans than in the hardest water. However, there ARE good things about having about 1 millimolar bicarbonate ion from a soluble bicarbonate. It brings the pH of the water to about the ideal pH for copper or brass stability. (Around 7.5.) It also buffers the brew water some to make the final espresso a bit less acidic. This buffer action also changes the way that acidic and alkaline components elute from the grounds. I simply purchase (inexpensive) distilled water, and add 1 mL of the 10% potassium bicarbonate per litre. Scale will never form with this, and the coatings of metal oxides on the walls of the boiler and group will be maximised and thus reduce corrosion. The inside of brass or copper boilers will soon have a dark and durable coating using this. The calcium and magnesium carbonate scale is porous and enhances corrosion, especially on elements. (Copper can react with oxygen, but not with water.)

Some coffees, I contend, benefit from using different amounts of potassium bicarbonate. The process of nearly cremating coffee beans to get really dark roast removes most of the acids in coffee, so potassium carbonate seems to me to have almost no effect on flavour. Adding higher concentrations of potassium bicarbonate will reduce acidity a bit more too, but I never do this.

Coffee contains massive amounts of potassium already, much more than the small amount that comes from this. Thus the only flavour change to the beans themselves comes from the bicarbonate ion.

MT (original poster)
Posts: 10
Joined: 9 years ago

#5: Post by MT (original poster) »

Right now I'm using Brita filtered tap water, but I tried distilled for a couple of weeks and that improved the situation only marginally.

As for steel getting into the boiler, that's an interesting question. When I purchased the new heating element it came with a screw that was drilled in to hold the pressurestat (the screw and nut are inside, the screwhead is on the outside holding the pressurestat). The original heating element did not have this screw, but the fixture was molded such that there was nothing on the inside of the machine. I was told this screw is either stainless of brass, but I suspect it's stainless. Would it react with the base of the heating element? The screw itself turned black for some reason, and needs to be wiped clean every couple of weeks.

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rpavlis
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#6: Post by rpavlis »

I wonder if the screw be not made of ordinary steel. That would present a situation similar to my machine when it had the M6 nut against the heating element. It was amazing how fast this made iron oxide. If the screw be in contact with the boiler water on the inside this surely could be the problem. Perhaps the manufacturer put in a steel screw when it was supposed to have been brass?

MT (original poster)
Posts: 10
Joined: 9 years ago

#7: Post by MT (original poster) »

I will take it apart this weekend and check. I'm afraid I'll have to send it to the manufacturer to make sure. I'll try posting some pics after I take it apart. Thanks for the help!

MT (original poster)
Posts: 10
Joined: 9 years ago

#8: Post by MT (original poster) »

Took apart the heating element. A lot of corrosion around the screw, some in the boiler. I will send it tomorrow to the person I bought it from and see what he says.

Cmtwgr
Posts: 134
Joined: 11 years ago

#9: Post by Cmtwgr »

For sure not brass
And it really looks like rusted steel ;o(

what does the bolt hold ?,

MT (original poster)
Posts: 10
Joined: 9 years ago

#10: Post by MT (original poster) »

On the other side (outside of the boiler) it holds the thermostat holder. The HE is stainless, it is possible that one of the bolts is steel, I guess.