Use of Central Heatn. Flushn. Agent to take off Rust?

[Ross365]

There's been a lot of interest in using citric acid for rust removal. Something that I've thought about, but never tried, is the stuff sold to flush out central heating systems.

I've been told that it is often made of sodium hydroxide, and possibly other chemicals, and it contains corrosion inhibitors. The idea is that it takes the rust off steel surfaces but does not attack the metal. I think it could be useful where citric is struggling to do the job.

The comment that's been made to me about using it in central heating systems is that it needs to be very, very well flushed out or it can cause problems afterwards and so I've never used it for that purpose. However, if you had some object in a plastic bucket or what ever, then when you take it out you could jet blast it to get all chemicals off it. Anyone got any experience?

 

[rikrobson]

5Kgs of citric acid is about the same price as a litre of central heating inhibitor, so unless you had a very cheap supply it would workout rather expensive.

Also it an inhibitor, not a remover

 

[Ross365]

No, there are two different products; the one you have in all the time is the inhibitor. Sometimes people don't use inhibitor properly, or at all, and the system becomes inefficient due to rust on the internal surfaces and collecting at low points of the circuit, so obstructing flow. To solve that there's a product usually referred to as a cleanser or flushing agent, which you use for just a couple of days and then drain down, all the muck coming out with it.

I think the flushing/cleanser product might work faster (and sometimes 'time is money') at removing rust than citric, but won't attack the metal. I hope that clarifies it for you.

 

[gaz1]

if you think them products work dream on

once a rad has sludge you wont power flush it as it cannot get around the corner and go along the bottom of the rad never mind up the rad panels themselves

sludge always hangs in the middle hence the reason why you get cold spot bottom middle of rad

left top and right are direct routes of flow

so what is in your rad is then sent down your pipes its not worth doing it that way

 

[Ross365]

@Gaz and @. - one of you is saying they are too feeble to do anything and one of you is saying they are a bit fierce.

I too had been told they are a bit fierce, which is why I've never used them. There are variables here; which brand are we talking about, just how badly is the system clogged and what sort of quality radiators do you have?

But, I'm not asking whether we should use them in our heating systems - I'm asking if they might be a more powerful alternative to citric acid to remove rust on stuff we are fettling .

 

[Kayos]

They react with copper if left in the system too long

I wouldn't bother, just use citric acid

 

[Kayos]

I might suggest that the cleaner is citric acid based? Only with the price tripled, or more? Maybe a few inhibitors added. Might even be formic acid with pH inhibitors? That was used that to remove cementitious residues from vehicles, over 30 years ago - worked well but eventually removed the galv on the landrover cab bits.

Modern cleaners are not simple chemicals, they target the specific composition of CH sludge

Check the mds, no citric acid

 

[waddycall]

Why not just buy some, give it a go and let us know the outcome?

 

[optima21]

with my central heating, I just drain it every couple of years and then refill and throw in some new inhibitor. and the radiators are still ok after 40+ years use.

if you're thinking of using citric acid, I left a small piece of steel in a glass of citric acid and this is the result after the water evaporated after a few weeks

nothing left of the nail.

 

[Ross365]

I'm sure that citric acid has been used in boiler cleaning solutions in power stations, but I don't know if it's been used in domestic systems.

In a heating systems, one of the things you want to do is get the rust particles to get suspended in the water; I think the term is flocculation, and a good chemical for doing that is sodium hydroxide, and that definitely needs an inhibitor with it (are those sometimes amines or nitrite compounds?).

I may well get some cleansing/flushing agent and try it on something like an old brake caliper, but I just thought I'd find out if anyone has already tried this, and looks as though no one has. In terms of reputable products, I'd guess that Fernox is up at the top, or maybe Screwfix will be OK and a bit cheaper?

 

[gaz1]

all depends on your plumber

the customer what they want to pay for

many wont pay for a full day to drain and power flush the whole system infact many dont like paying half a days work just to do a clean of the system

As you say, variables, thickness of radiator steel, degree of contamination etc, this is why I flushed mine first and removed lots of the sludge; there are different grades of cleaners and if you remove most of the sludge first you can use a mild cleaner for rust removal only. This was based on his 40 years as a plumber.

One other point, by regularly cleaning them, say every 5 years, it prevents a lot of the sludge build up.

your pipes also have an effect on any system minibore can cause loads of issues when sludge is involved

the main point is the inhibitor for new and old systems

the problem is cleaning old systems

one thing to remember with a flushing agent if you have one bad rad thats rusty or has been rusty at the bottom of it it can leak

 

[gaz1]

There's been a lot of interest in using citric acid for rust removal. Something that I've thought about, but never tried, is the stuff sold to flush out central heating systems.

I've been told that it is often made of sodium hydroxide, and possibly other chemicals, and it contains corrosion inhibitors. The idea is that it takes the rust off steel surfaces but does not attack the metal. I think it could be useful where citric is struggling to do the job.

if its your system go ahead try what you want

if it goes bang / leaks or floods your house then its your tough luck

some of the inhibitors have been on the market a long time flush agents are roughly the same but cannot beat taken off drained and flushed the whole system

if you have a hot water cylinder plumbed into system it can be a whole nightmare to deal with

 

[Ross365]

@gaz1 please read again post 6 where I pointed out;

"But, I'm not asking whether we should use them in our heating systems - I'm asking if they might be a more powerful alternative to citric acid to remove rust on stuff we are fettling".

This thread is not about CENTRAL HEATING or PLUMBERS!

 

[Myles1970]

@gaz1 please read again post 6 where I pointed out;

"But, I'm not asking whether we should use them in our heating systems - I'm asking if they might be a more powerful alternative to citric acid to remove rust on stuff we are fettling".

This thread is not about CENTRAL HEATING or PLUMBERS!

... If I had any hair, I'd be pulling it out following this

 

[grim_d]

... If I had any hair, I'd be pulling it out following this

Skim reading is somewhat of an issue on here sometimes.