PegSneggle
Materials
- Dec 3, 2003
- 1
I'll set the scene and then ask my questions. Feel free to give short sharp answers.
I have a domestic central heating system which is quite old and is based on a good quality boiler with a cast iron heat exchanger.
The boiler knocks and bangs due to the presence of sludge, I guess. I want to clean it out and my researches tell me that phosphoric acid is the ideal chemical, as it attacks the rust sludge with enthusiasm and is much kinder to the cast iron.
Questions
1. How much should I dilute the acid before putting it inside the boiler? (The acid I buy will be supplied at maximum industrial strength. The salesman mentionned 85%, but I don't know what he was talking about)
2. Should I run the boiler whilst it has the acid inside to improve or speed up the action?
3. I will clean and flush the boiler a number of times, to be sure of removing all the sludge. Is there an easy way to tell from the emerging acid, whether the sludge has all gone or whether I should repeat the cleaning process.
4. Any advice as to how long the acid should be left circulating within the boiler?
5. Will the acid harm the copper pipework held together by lead solder.
6. Do I need to do something to neutralise the system, once the process has been completed.
7. Apart from the obvious safety precautions of goggles, gloves are there any major pitfalls.
Please reply even if you can only answer some of these questions.
Many thanks in anticipation of a reply
I have a domestic central heating system which is quite old and is based on a good quality boiler with a cast iron heat exchanger.
The boiler knocks and bangs due to the presence of sludge, I guess. I want to clean it out and my researches tell me that phosphoric acid is the ideal chemical, as it attacks the rust sludge with enthusiasm and is much kinder to the cast iron.
Questions
1. How much should I dilute the acid before putting it inside the boiler? (The acid I buy will be supplied at maximum industrial strength. The salesman mentionned 85%, but I don't know what he was talking about)
2. Should I run the boiler whilst it has the acid inside to improve or speed up the action?
3. I will clean and flush the boiler a number of times, to be sure of removing all the sludge. Is there an easy way to tell from the emerging acid, whether the sludge has all gone or whether I should repeat the cleaning process.
4. Any advice as to how long the acid should be left circulating within the boiler?
5. Will the acid harm the copper pipework held together by lead solder.
6. Do I need to do something to neutralise the system, once the process has been completed.
7. Apart from the obvious safety precautions of goggles, gloves are there any major pitfalls.
Please reply even if you can only answer some of these questions.
Many thanks in anticipation of a reply
