Advice on cleansing central heating system

[wesayyes]

Have inherited a neglected system. System is now 15 years old. Radiators seem in good shape, no leaks. Fully pumped, Ideal classic boiler, F/E tank in the roof, hot water cylinder and mid-postion valve. 15mm feeds for the radiators upstairs and microbore downstairs. [drop-down is the technical word?]

Anyway, by flushing system with Sentinel X400 for several days, then refilling, have got rid of any brown sludge that was loose. The F/E tank had 2
inches sludge in the bottom. There was also a heavy black staining of the flushed water with some black gritty bits.

The mid-point valve needed replacing. While doing this, removed Grundfos pump and cleaned what I could access. All around the pump, the old mid-position valve, and pipes between the 2, there is a black, gritty deposit that feels like coral. Is this iron + calcium carbonate [magnetite?]

Presently getting good flow rates around system. Boiler works well and only very slight kettling noises. Hardly noticeable.

Question is how to flush system to remove some of this hard gritty stuff stuck to the pipes? Confused as I understand most powerflush advocates would use an acidic solution but the Ideal boiler has an aluminium heat exchanger - or so I understand. Then again, would careful use of Fernox DS 40 with immediate neutralisation be so damaging?
Or will something else more slowly but safely dissolve this stuff?

Any advice gratefully received.

 

[bryanpar]

hire a powerflush machine these are usually quite good at removing most rubbish from your system.if you get a company in to do it ti will cost you around £300

 

[wesayyes]

Thanks, but I still would not know what chemicals to use, or would the hire firm tell me? £300 for a properly carried out powerflush sounds cheap [13 rad system]. Was quoted around £800 by one firm.

I think yes, could do it myself, but reluctant as system flow good at moment. It is just trying to get rid of as much 'magnetite' as possible without invasive flushing that seems my best move.

 

[45yearsagasman]

That hard black deposit inside the pipes (most likely in the airing cupboard) will not be removed by powerflushing alone. If it is severe, then remove the affected pipework and manually clean the pipes or replace with new pipework. I have found that long term this is the route to go down. I do not advocate harsh chemicals in older systems, buts others will disagree.
You sound as if you are quite competent to rectify this problem yourself without vast expenditure. £800!!!! is ridiculous.

 

[wesayyes]

45yearsgasman

Thanks. Some of the pipework can be cleaned without resoldering etc. And happy that you agree with my original thought, which was manual clean only real way to deal with the hard black deposits.

One question - is there a flexible wire brush can use to clean inaccesible pipework? Or round the bends of curved / 90 degree pipes? Has someone ever made something that rotates say on the end of a drill? Obviously there would be a risk of jamming/ breakage but would have thought something along these lines has been thought of?

Cheers

 

[mickyg]

dont get carried away, if you've got microbore you could end up doing more harm than good by dislodging chunks. You'll probably find the worst of it is around your feed and vent connections, pump and the first few feet after the pump. Just replace this section, maybe another run with x400, but dont get carried away.
I wouldnt recommend diy powerflushing full stop let alone on microbore.

 

[expertgasman]

How about just fitting a magnetic filter on the return?
http://www.fernox.com/equipment/filters/total+filter+tf1

 

[mickyg]

How about just fitting a magnetic filter on the return?
http://www.fernox.com/equipment/filters/total+filter+tf1[/QUOTE]
yeh i'd agree, good suggestion.

 

[xr4x4]

If it where me I would also flush system again with clean water, run a cleaner again, then flush again with clean water then top up with inhibitor.

As you have already got over the worst, I cant see this doing any harm.