Domestic heat exchanger cleaned with HCl 3

[aj34]

Just read a post on another forum where it was suggested that conc. HCl be used to clean (presumably chalk) from a domestic boiler's plate heat exchanger, which I assume would be of SS construction (316, 304, other?). I appreciate the contact time would only be minutes before it's flushed through but do you think this practice is acceptable? Could such cleaning lead to future problems (pitting, stress corrosion cracking) or is a short exposure not a problem.

Interested to hear opinions.

 

[metengr]

aj34;
No, I would not recommend using HCl in heat exchangers because of damage to the tube material and safety in handling concentrated HCl.
You should search the internet for safe cleaning/descaling agents for domestic heat exchangers or industrial heat exchangers. Information given on any internet forum should be given a sanity check.

https://www.google.com/search?sourc...g+agents+to+remove+scale+from+heat+exchangers

 

[unclesyd]

I concur with the above post that HCl is too hazardous to use for you project. One thing most people don't realize is that you can use HCl as is on bricks and stone, it's use on metal for cleaning metals requires an additive package that contains inhibitors, wetting agents, rinse aids, etc.

Below is link to a material called Rydlyme which I've used many times with very good results. It might be applicable in your case. The only drawback is that it is a little expensive, but restoration of the heater efficiency will justify the cost.

 

[EdStainless]

As Met said, the inhibitor packages are rather involved.
You have to get the concentration of both acid and additives correctly balanced for what you are trying to remove.
I don't like HCl for use on SS because any miscalculation almost assures that you will damage the equipment.
Syd is right, the commercially available packaged descaling treatments may be expensive but they work (when you follow directions exactly) and the risk is small.

To start with you take samples of your scale and have it tested for acid solubility. Make sure that it can be removed by the product in question.

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Plymouth Tube