Heating system corroded? Water is dark green and pump seizes

Hi,

A few years back I had a Main 24 combi put in and it worked fine till a year or 2 ago when the pump seized and had a new on fitted. Since then I've had the system power flushed (twice, once last year) and since November last year the pump has seized 5 times, needing a new one each time.

I've had a Fernox magnetite filter (Total Filter) fitted but the last pump lasted 8 hours before it seized

I'm having it flushed again with Fernox system cleaner and neutraliser (plumber was advised by Fernox to add those) but have a horrible feeling I'm going to have replace the whole system, pipes and radiators.

First of all, could sludge (the waters dark green with little black bits, and there's an oily film on top, stinks as well) cause the problems with the pumps and will the system cleaner/neutraliser get rid of the problem, or will it just come back thanks to radiators already been corroded (assuming they are).

How much am I looking at to replacing 10 radiators - (2 medium double panels, 2 large double panels, 4 small doubles, 2 single long) and associated pipework in a medium sized house (I apologise if I just asked how long is a piece of string )

Sludge in a system is probably the biggest cause of CH breakdowns. Yes, it will cause a pump to seize, as well as any other moving parts.

A system should only need flushing once, properly, and i'm finding it quite worrying that you're having it done a THIRD time! Either it is not being done properly (ie full day with the correct machinery and chemicals) or there is a system design fault (which is unlikely).

Treated correctly, a pump and system should run up to 30 years, as it has no bearings, the water acts as the 'bearings', and muck, debris, sludge-call it what you want, will clog it up in no time.

British Gas do flushing, and although it isn't cheap, in my experience they are the only ones who do it properly, while offering a lifetime guarantee. Nobody else offers this as far as i know.

Hope this helps, good luck!