What's the worst case if I leave Sludge Remover in permanently ?

[Rick the Spud]

To cut a long story short, after a BG callout to replace a blocked/scaled pump (didn't see the pump myself so not sure) i was quoted £1200 for a power flush and new pipe work (because it was so sludged apparently) to which i said 'balls' and investigated it myself.

After cleaning the expansion tank, several system flush throughs until the water ran clear (it was pretty black), and a drain down and refill to fit a Fernox TF1 filter (can't recommend them enough) the system has been running fine all summer on hot water only with inhibitor added just to be sure. the TF1 has been emptied several times with only the first emptying containing any decent amount of crud, since then it's just been about a tea spoon full of black oxide.

I waited until more recently when i needed the heating on, then added a descaler (which can be left in) and a sludge remover, which says to leave in a maximum of 3 weeks on a normal heating cycle. since adding it, my filter has not really been catching any extra crud which i assume means the system is fairly clear.

Now my question is what happens if i leave the sludge remover in the system for longer? Obviously without a filter the sludge remover is designed to break down the oxide and get it moving in the system to be flushed out at a later stage, but if there's no more sludge left in the system, and my filter is catching what little there is, can i just leave it in there, or will the chemicals it's made up from start eating away at certain parts of my system, etc?

 

[tamz]

Depends on which cleaner you put in but i guess it is something like X800 or F5. They are not as corrosive as they once were but i would get it washed out.

 

[twistednuts]

Wouldnt like to say for sure, but it wont do it any good.

Have you tried aggitating the rads? Ive heard this really removes the sludge, never tried doing this personally.

Id drain it down and add some F1 just to be on the safe side. TF1s are very good, but they always seem to start leaking on the tap fitting at the bottom. Its only put on with some kind of thread seal gunk.

Dont know if you know this, i found out by accident, the black blank cap at the bottom of the tap acts as switch for the tap, ruddy fantastic!

 

[Billy Bob Bob]

x800 used to be feroquest it would eat aluminum

 

[Rick the Spud]

Tradesave stuff from PTS, TSSM-2 Non Acid De-Scaler, and TSSM-4 Sludge Remover.

My only guess is that the inhibitors etc in the system from the previous owners were keeping sludge/oxide in suspension and keeping the rad/pipe surfaces clean inside, it just had no-where to go until i drained/flushed the system?

Does this make sense or am i talking nonsense?

 

[Rick the Spud]

Wouldnt like to say for sure, but it wont do it any good.

Have you tried aggitating the rads? Ive heard this really removes the sludge, never tried doing this personally.

Id drain it down and add some F1 just to be on the safe side. TF1s are very good, but they always seem to start leaking on the tap fitting at the bottom. Its only put on with some kind of thread seal gunk.

Dont know if you know this, i found out by accident, the black blank cap at the bottom of the tap acts as switch for the tap, ruddy fantastic!

haha, err, yeah twisted nuts, i thought that was obvious!
Where do they leak, around the very bottom or the tap on the side, mine seems fine for now, must have emptied it about 20 times now.

how do u aggitate the rads?, is that with a rubber mallet jobby?

 

[twistednuts]

Hahaa, it wasnt even me that noticed the black tap thing, it was my mate!

Yeah, the chrome tap at the bottom screws onto the black plastic body of the TF1, with some king of green thread sealer. Ive had a few leak and so has my mate. At first i thought it was where the main body screws onto the valve part, where you have to fanny about with different o rings if you change the orientation of it.
Some ptfe on the threads sort it if it does eventually leank.

You can buy drill aggitaters that fit onto a sds drill, but a rubber mallet might do the trick

 

[Rick the Spud]

nice one, cheers. i'll keep my eye on it!

 

[fuzzy]

i went to a leak at a fire station once, i cut into the steel pipe and it was just sludge. it took a few hours to clean up were it spread.

2 months later i was called back and replaced another section, ive since bene back at least 10 times

 

[Rick the Spud]

would a de-sludge not help?

 

[fuzzy]

its way past that i think mate, massive system

 

[flyboy]

Hmmm, this has got me wondering. I have a chemistry background. Sludge remover must be some sort of chemical (acid?) that dissolves the sludge, at the same time it will be dissolving metal (hence the warning not to leave it in for more than 5 days?). As the sludge gets dissolved the acit chemical will get used up, its being neutralised. If there is "just enough" chemical added (which you cannot reliably judge) all the sludge will be dissolved and ALL the chemical will be used up - at this point there will be no more of the chemical to dissolve the metal.

Then I thought about my heating system. 30+ years old, originally had a cast iron boiler (replaced a couple of years ago and I am using half as much gas). The system never had any inhibitor in it until the new boiler installed. No leaks apart from 3 pinholes in the copper pipe that supplied the cold water directly into the boiler - hence very little flow in the pipe. (same tube used on whole system - only leaks in this one pipe - must be strange stagnant conditions in that pipe?)

Does inhibitor work? - is there any evidence it does. Manufacturers tell us that it does - is it a myth? When I had the new boiler fitted it had £60 worth of inhibitor put into to maintain the g'tee. Nice profit for someone if it does no good. (but perhaps it does some good in some unusual circumstances?)

I remember reading long ago that you can get red or black rust in a heating system. Red rust happens when there is a lot of oxygen in the system - perhaps you have got a leak and a constant (but slow) flow of new water containing dissolved oxygen into the system. And the rusting continues as more oxygen reacts with the iron - eventually the rad will rust through. If the system is airtight gets no extra oxygen that is dissolved in the water then you get black rust, once the oxygen is use up then no more corrosion of the iron will take place. This is why a car can rot away in 10 years (lots of water and oxygen). A wet radiator can last for 30+ years? I think black rust forms a film over the steel and this helps stop further rusting.

Remember the science experiment? Steel wool in a test tube along with water and wax. Boil it to drive out the dissolved oxygen in the water. The wax melts and float to the top. When cool you have a solid plug of wax that keeps out the air (and oxygen) and the steel wood does not rust even though its in water. Steel wool in a test tube with just water rusts away to give the the red rust - because there is lots of oxygen in the air, dissolving into the water.

The black rust you get in radiators is magnetic and this is what sticks to the Fernox filter. I had one fitted after a power flush. After a few days there was loads of black rust sticking to it, this was cleaned off (the power flush had dislodged the magnetic iron oxide (black rust). Examining the filter a year later there was some black rust on it - but not much, either there had not been much more corrosion or the black rust was staying where it was.

Now you can get electrochemical corrosion - where two different metals touch and produce an electric current and this dissolves one metal (which is what happens in a battery). This is much more complicated and I don't begin to understand how you stop it. But if you have a boiler with an aluminium heat exchanger this would be the killer if conditions were right - this is why the manufacturers stipulate you must have inhibitor to maintain the g'tee. When two metals touch the most reactive dissolves in suitable conditions. The order of reactivity goes aluminum, iron, copper, so if the metals are touching then the aluminium would corrode first followed by the iron and then the copper.

Also back to the original question. The sludge remover works fastest at the start as it most concentrated. As it works it get used up, hopefully after 5 days most of its used up. So some metal will have got dissolved and as time passes more metal will dissolve - but as the acid gets used up it will work slower and slower at dissolving the metal. So flush it out when you can, the sooner the better, but I would not panic unduly. (but someone with more practical plumbing experience might differ)

 

[Rick the Spud]

wow, cheers for that. an interesting read for sure.

thinking of draining in the next couple of days.

some more questions!

1. to do a flush is it best to drain down and refill (which before has settled sludge in pipes and blocked them), or do what i did before and drain from the bottom rad but with the expansion tank still adding water, until it runs clear from the bottom rad, then stop draining, run heating to stir it all up, then run drain hose again until clear. repeat until it runs clear almost straight away. also means u get no airlocks.

2. not suggesting i will, but what would happen if u put normal household descaler in your system?

 

[doitmyself]

Hmmm, this has got me wondering. I have a chemistry background. Sludge remover must be some sort of chemical (acid?) that dissolves the sludge, at the same time it will be dissolving metal (hence the warning not to leave it in for more than 5 days?).

Fernox DS40 is definitely acidic (pH 2-3) and you have to add a neutraliser (pH 11.8) afterwards. The other Fernox cleaners are virtually neutral (pH 7.0-7.8)

Sentinel X300 and X400 have a pH of about 7 and X800 is 6.5. Sentinel Deposit Remover has a pH of 3, but they don't supply a neutraliser. All they tell you to do is flush through with water until the pH matches the mains water.

Most of the products are described as "synthetic organic polymers".

 

[woodsy]

I was told by sentinel that the x800 will eventually just break down if left in the system as it is some sort of organic material but to be honest, i don't understand why when you have gone to the trouble of trying to desludge a system you would leave it in.