Badly Sludged Pipes

[Adyonline]

Hi All,

I'm in the process of changing out my boiler for a new and since the pipes from the boiler are currently cut I noticed a very heavy build up of sludge in the pipes (approx 1mm thick).

Last year I took all the radiators out and flushed them until the water ran clear - which took alot on some. I dont have any cold spots on the radiators.

The system had still been running with black water so before I changed out the old boiler I ran 2 litres of de-sludger through the system for 1 week just to ensure the new boiler wouldnt be affected by exsisting sludge. The water ran clear after the clean-up.

The sludge is more of a scale as it is hard - but will disolve back into sludge when scraped with a screw driver.

So my question is, - is this sludge/scale a problem for my new boiler and if so how can I do more than I have already done ?.

The system is 30 years old and some of the pipework is underground so checking for leaks when using a harsh de-scaler isnt an option.

Cheers,

Ady

 

[fitz1]

start fresh and repipe.only guarantee.better safe than sorry.

 

[Agile]

What was the "de-sludger" which you used two litres of?

They are not all the same!

1 mm of sludge on the wall of a 22 mm tube is not a lot and quite manageable with the right methods.

Who is the CORGI fitting the new boiler? What does he say about it? What is the model of replacement boiler?

Tony

 

[Adyonline]

Hi Tony,

I used the x400 sludge remover.

The replacement boiler is a Grant Vortex Utility 15/26 condensating.

I'm an instrument tech (a high psi industrial plumber ) by trade and have installed a couple of C/H systems from scratch before and since its an oil boiler I'm installing myself via the Building Regs route.

I've been quite worried about the underground pipes for some time as we've already had one obvious leak after I cleaned the rads last year - the quality of the pipework was very poor (or more to the point, the joints). So I think i'll take the plung and drop down feeds for the down stairs rads.

I'm also planning to install a thermal heat store if that makes any difference ?

 

[chrishutt]

You might want to read the post on mains flushing in the FAQ topic above or in the Wiki.

My experience suggests that there is often a residual problem after any flushing/cleaning operation because a scaly deposit will often persist on pipe and radiator walls. If this stayed in situ it wouldn't matter much, but having been weakened by the chemical cleaning it is liable to flake off, perhaps months or years later.

For this reason I generally fit a return filter to avoid these flakes passing into the boiler where they might block valves or heat exchangers. Of course the return filter itself might then need regular cleaning so I set them up with a reverse flushing mechanism to facilitate this. A Magnaclean or similar might be an even better option, but pricey.

 

[Agile]

X400 really needs to be in the system for about 3-4 weeks.

X800 is much faster and one day or less is enough.

Both are non acid and if the system is bad them a citric acid based cleaner is much better but of course risky for a system in poor condition.

My suggestion is to pressure test the pipework before renewing it. Was your system pressurised before? I assume it will be pressurised with the new boiler?

Tony

 

[Adyonline]

Thanks for the feedback - I know how to flush a system and the system is running clean, hence this post.

I have seen the MagnaClean and I think I might put one in line to be safe.

I cant find anyone online who sells on X800, but I have already bought Fernox Heavy Duty Restorer to cleans the system once I've finished working on it.

Good idea on the pressure test - the system is a vented (header tank) style and for simplicity I've kept it that way (there are also 20 rads on the system so I was conserned the expansion & losses on a sealed system would cause problems on such a large system).

 

[Agile]

There are still places which sell physical goods over the counter!

X800 was previously rather stupidly called Ferroquest !

I kept telling them that they were stupid to diverge form their simple X*** format and apparently they have eventually agreed!

Tony

 

[ChrisR]

filter itself might then need regular cleaning so I set them up with a reverse flushing mechanism to facilitate this.

How? With 4 valves??

 

[Agile]

Standard "diode bridge" configuration I presume!

Tony

 

[chrishutt]

How? With 4 valves??

Yes, one of which is from the filling loop, so no big deal. Even 22mm ball valves are only £4 or so, so it's not an expensive set-up, and the isolating valves are easier to use than the usual boiler isolating valves, so system flushing is much easier. I generally use a 1" filter to reduce resistance and cleaning frequency.

 

[Adyonline]

Thanks Tony - I Will have a look for that.

I live in the middle of no-where and work even further away from anywhere - I do nearly all my shopping online

I've currently got the pressure test underway at 2 bar with no obvious leaks as yet. Bearing in mind this is a normally vented system, do you think I should take the test any higher than 2 bar ?.

Cheers Ady

 

[Adyonline]

Pressure in the system fell by 0.5 bar overnight and then stabalised at that pressure (1.5bar) - I'm assuming the inital loss was leakage from the rad valves and therefore the pipwork is ok.

 

[Agile]

Its possible that there was some air in the system which took some while to dissolve.

I dont agree with your odd suggestion about leaking rad valves. They just leak and leak and leak....

Tony

 

[Adyonline]

'Odd Suggestion' ?? I think its odd to assume that Rad valves will eather leak or not leak. Any valve may be prone to leaking when under certain conditions and will often re-seal when the pressure or tempature is changed.

There is no water in the system - I did an air pressure test, the system has now held up for more than 24hrs under pressure at 1.5 Bar.