After, ahem, numerous bans 
JohnD hated me on GD:mrgreen:
Sounds like your silting is due to the old radiators Annie, it has probably been lurking in them for years. The cheapest idea would be to remove each rad and flush it out with a power jet.
Sometimes flushing the whole system doesn’t remove the stubborn sludge residing in the oldest rads which could break away and contaminate the rest of the system…
JohnD - worra plonka he is…
Indeedy;-)
That would take the same time as a flush ogf.
If a reverse flush is carried out, all will be fine. It will also remove any crud in the boiler heat exchanger, which flushing the rads alone would not…
Agreed. Personally, partly because I’m capable ;-), I’d take off each rad and flush them through and then the whole system as a matter of course before adding chemicals. But you know that anyway:-) Cheaper than a powerflush and possibly more effective
5 year old boiler should clear easily enough, subject to how much shite has got itself into the seals
Yep,
That’s what I would do if it were my system.
However, if you don’t have that capability, you’re stuck with paying others to flush it…
Yes, I see where you are coming from Fender, the system is probably already contaminated…However, my system is over forty years old and until recently was working from a back boiler and a header tank in the loft. I always remove a radiator and flush it out when painting a room. Never had a problem with silting. Do you think it could have something to do with it being a single line feed system? The bloke who fitted our new Bosch Combi boiler didn’t like fitting it to a SLF system, but we’ve had it over two years now and it’s brilliant…
Notoriously difficult to balance 
Should not make too much difference mate.
What’s probably helped over the years is you flushing the rads whenever you removed them.
I don’t think too many engineers try to balance them these days anyway do they?
Imo, a lot of “engineers” these days are nothing more than fitters, with a pee poor fault finding ability?
Agreed. Shove a couple of 22mm main feed/return circuits with 15mm (Hep2o, heaven forbid ;-)) sub-runs and let the TRV’s do the rest. 
:shock:
We are on the same wavelength…:-p
There’s nothing like a bit of fine copper bending “art”
Bloody Hell!..:shock::shock::shock:
Thanks guys but I think I am getting a migraine! I am sure we had just a powerflush before but then it all went belly up again. Is there anything wrong with sealing the system? It’s a lot cheaper than the quote for changing the radiators.
Why change the rads?
Sounds like the last flush was not done properly and inhibitor not added.
Nothing inherently wrong with going over to a combi if that’s what you want. Will be cheaper to run anyway.
It’s just that from what you’ve said, it’s not really needed.
I bet us guys could do the job in an afternoon Annie…
Well…Fender and Dex anyway, I could carry their stuff and make the tea…
Coffee white with one please…
No problem Fender…