Removing hard black crust in heating pipes (not limescale)

[RegB]

I'm moving a radiator and have cut the pipes to it. Inside the pipes there are big flakes of hard black crust , some up to 5mm across. Some of these are neatly curved, so must have formed on the inside of the pipe and come away. It can't be limescale because this is a soft water area so I think it's some kind of iron oxide gone solid. Anyway, I'd like to get rid of it but don't know the best way. Does anyone know if this stuff can be dissolved with a chemical and then flushed out in a power flush, or am I going to have to cut out the pipes and manually clean them? Any advice greatly received.
Reg

 

[ljrgas]

When powerflushing the engineer should use a chemical to remove the sludge that's in your system

I normally add a chemical 1 day before to try and make the job easyer when I flush it the next day
Sometimes if it's really bad you need to cut it out

 

[JohnD]

As you can do DIY plumbing, this would be a good time to fit a system filter to the return pipe by your boiler so it traps these particles. You will find they are attracted to a magnet. The Sentinel and the Fernox filters are good.

Yes, you can get cleaning chemicals to loosen and break down this sediment. I like Sentinel X400 as a DIY treatment, which is very mild, non-acid. there are stronger and faster ones. If you fit a filter you can then add their other product (I forget the name) which prevents particles settling so they circulate round and are trapped in the filter long-term.

If you pay someone for a powerflush it will cost hundreds of pounds and (should) take half a day.

 

[RegB]

Thanks irjgas, and that's useful info. The trouble is this stuff is not sludge but hard black flakes, some quite large. I don't think the usual power flush chemical would dissolve this so I'm wondering if something else will.

 

[ljrgas]

its iron oxide

a engineer will use a decent chemical that will dissolve it while powerflushing

but as I said if its really bad the engineer may have to cut out parts of it
also not sure of the size pipes you have but if its microbore you would b better off cutting it all out and re-piping in 22-15mm tails

as above what john has advised (good advise) however I prefer a spyrotec also ive been to jobs where its took well over half a day to flush out it really depends on how bad the system is

 

[RegB]

Thanks to both of you for that really helpful info. I was just telling the wife it's about time we got a sludge filter but for some reason she seems to prefer earrings. Can't imagine why. Anyway, your replies have strengthened my case. I'll check the Sentinel and Fernox ones. I also found a few deals on that Adey Magnaclean. Do you know if that's any good?

 

[JohnD]

they leak

http://uk.search.yahoo.com/search?o...chr-nectar&slv8-&type=61465&p=magnaclean+leak

 

[Agile]

To dissolve sludge you need an acid and that can damage the rad valves and even make the rads themselves leak.

Mostly based on citric, malic and phosphoric acids.

Tony

 

[RegB]

Thanks to you all for those replies. They were very helpful.

 

[Dan Robinson]

Magnaclean are the most effective at catching dirt and the new ones are perfectly leak free.

Every TF1 we we fitted has leaked from multiple places and will be replaced as each boiler comes round for servicing.

JohnD is a keen amateur and has very limited experience.

Not having a pop, and not mentioning PTFE . .

Following that link reveals little more than ancient threads and/or questions by diyers with even less knowledge and experience.

 

[ChrisR]

Look up "mains flush" here. You can do quite a lot of good by blasting out whatever will move. To be effective you need to work out your heating system (draw it, with the valve(s)) and shut things so you're forcing water through one rad at a time and not having it short-circuited by the boiler or cylinder. Don't forget to deal with the f&e tank, and vent.
Fernox DS40 and Kamco FX2 will dissolve it, but need neutralising afterwards. They find weeps.
X400 is gentle, other Fernox chems and Sentinel X800 are in between. There are several others.
One of the last boilers I took out had been powerflushed ( a one day not too aggressive sort of job) by BOTH British Gas and a Powerflushing Company (red elephant one, normally ok) but the pipes from the boiler were still only about 8mm diameter clear, inside the 22mm copper.
If 'twer mine I'd mains flush it, put X400 in for a few weeks then repeat the flush, then maybe fit a filter, depending on the boiler type/age. Big/old/iron are less fussy. Combis much more.
Unless it was really clean I wouldn't put inhibitor in - it sticks to suspended particles of oxide and makes a slimy mess.
Your flakes can stack up and block things, but "grubby" liquid? You could have Guinness in there, as long as you've got enough flow, it does the job, in an oldie.