thescruff wrote on Jun 22nd, 2011, 11:44pm:Magnaclean should be in the return not the flow.
As should other brands.
Yes, I fitted a Spirotech Magnabooster in the return right next to the boiler before we started doing much flushing. Then once we started to flush with mains I found that the pipes were becoming re-blocked as disturbed magnetite was circulated by the central heating pump. Yet at this time the Spirotech was collecting very little

.
So as you said you had a Magnaclean and it worked well I bought one of those as well. The only space I had to fit it was on the flow out of the boiler so that is where it went.
After one hour with the heating running the Spiro had literally a couple of bits of black to wash out whereas the Magnaclean had more than an eggcup full of solid black hard bits.
Since fitting the Magnaclean (in the flow) we have had no re-blocking of the pipes and while the system was dirty the Magnaclean would collect at least 100 times more bits than the Spiro. (I haven't cleaned it out since re-filling the system with Fernox so don't know how well it is doing now).
So even though it is not in the right place the Magnaclean is outperforming the Spirotech by an enormous margin, I did wonder if the Spirotech could be faulty?? It is very smart but it seems to me that it can't cope with a dirty system.