What Causes Sediment Deposits on Copper Pipes in a Central Heating System?

Question

Hello I have deposits on the pipes as in the attached photo, tell me what this may be caused by? It was created some time after the boiler was in operation. Is it normal?

viayner · Answer

Hello,
There may be several sources, for example:
- water codensation, in a slightly alkaline/acidic environment and you have corrosion products
- leaks of water containing a lot of carbonates (hard water), evaporation of water and crystallization of carbonates.
- if you have contact of different metals, you have "electrochemical" products, a cell is created.
Regards

matgor23 · Answer

Could this cause air to appear in the installation?

viayner · Answer

Hello,
it looks like surface deposits, I don`t know what your environment is? brazed pipes - how are they connected? Warm water accelerates corrosion processes, although copper is a metal on the "precious" side, corrosion occurs, it`s all a matter of conditions.
Can you determine the source of the problem? leak, thin stream or rather condensation?
Regards

matgor23 · Answer

There are no leaks. The environment is as in the second photo, i.e. just an ordinary home boiler room, about 6 m2

slider2002 · Answer

In my opinion this is the norm. copper reacts vigorously. these deposits should be easy to remove.

Anonymous · Answer

In my opinion, these deposits are caused by the flux used when soldering the pipes.

Plumpi · Answer

Such deposits are the result of the sloppiness of the installer who did not want to clean the tubes after soldering to remove any solder paste remnants. Solder paste contains acids and powdered tin.

VPS · Answer

That`s why it`s always worth having a damp microfiber and ALWAYS wipe the place after soldering. You can then paint with copper spray. Buy yourself a copper pipe cleaner and clean these places.

Zbigniew Rusek · Answer

Yes, copper is rather resistant to corrosion, but slightly less than brass (an alloy of copper and zinc), in which the addition of zinc increases the resistance to oxidation.

zwiezda · Answer

What is this coating on the copper pipe supplying gas to the stove? what to wash it off and preserve it with?

viayner · Answer

Hello,
Copper is subject to corrosion, depending on the environment, it may be oxides or sulphides (these are the most common), the greener ones are basic carbonates - malachites - see church roofs.
These are surface raids.
Regards

bratHanki · Answer

The installation was made with brazed copper solder with an admixture of several percent phosphorus, so this coating may be some of its salts.

olekolo · Answer

And today, using an inspection camera behind the bathtub, I saw something blue on the radiator pipe. It looks like a piece of mortar that has turned blue, is this normal?

viayner · Answer

Hello,
this is malachite, a basic copper carbonate, formed as a result of the corrosion of copper in an alkaline environment, a completely normal and surface phenomenon, compare, for example, the roofs of churches covered with copper. The color may be between green and blue, depending on corrosion conditions
Regards

olekolo · Answer

Thank you for your answer. So it won't eat through my knee

I know that a greenish coating is normal. I was surprised by the blue one. The backlight may be a bit misleading, but the blue one surprised me. And I'm a bit oversensitive because in my previous apartment everything was made of indestructible copper and it washed out my elbow

viayner · Answer

Hello, it all depends on whether the environment in which this element works is acidic or alkaline, more or less humid, etc. it is still the same substance but with a slightly different relative composition. Regards

olekolo · Answer

Cool. I see. And one more question. Because I understand that the pipe itself is covered with malachite. But it looks like it would be thicker. If the mortar from the tiles fell and it was covered with malachite, there is no possibility that the tile or plaster glue would react in such a way that it would eat away at the elbow?

viayner · Answer

Hello.
Since you mention that you may have, for example, plaster on a copper pipe and the whole thing is in a corrosive and humid environment, you probably have a layer of plaster saturated with copper ions and they react to form the above-mentioned malachite on the copper surface.
Note that if the entire pipe is in a corrosive environment and, for example, immersed in water, all the water will be susceptible to the formation of malachite, and it will form where it is easiest to initiate crystallization, i.e. porous places.
Copper corrosion is rather superficial, what may be dangerous is the formation of an electrochemical cell, i.e. contact of two metals (different, with different potentials) and the contact is ensured by an electrolyte (water with some salt). In this case, the more active, less noble metal will be damaged.
Regards.

olekolo · Answer

I see. Thank you for your answer, I will sleep more soundly. It`s all in copper there. The tubes are in the air. They don`t touch anything. Thanks and it`s no longer poisonous.

Michaljaros1 · Answer

Hello.

I will join the thread with my problem.
Basically, after reading this, I know more or less what and how.
I have a copper gas installation in the hen houses. Chicken manure itself contains a lot of nitrogen and ammonia.
In addition, when cleaning, I use ammonia, sodium hypochlorite, lime and many other substances.
Is it possible to check whether it is a surface sediment or whether it has gone deeper?
The closer to the ridge, the worse, but that`s where the moisture comes in.
In the worst places it fades to black.

Regards

What Causes Sediment Deposits on Copper Pipes in a Central Heating System?

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