askng Q. on bhalf of someone.

was is the consensus of getting a powerflush done to clear central heating radiators?

price quoted £ 700 ... but looking in screwfix catalogue, I am sure replacing the radiators would work out to be 1/3 to 1/2 that price. (radiators have a bolt on attachment so providing the wall hanging is the same, it is not a big job to replace)

problem is that radators are cold in the central bottom section due to build up of sludge , so is this same sludge blocking the pipework too?

are new radiators the better option?

I had a similar problem some years ago, in a previous property. I removed each rad, (carefully), one at a time and flushed them out with a hose. Refilled with Fernox added when all done, and had no further problems. Can't say if this the correct way to do it, but it worked, Cheers Ray

If replacing the rads you'd have to fully flush the system first or just clog them up again. Chances are if the existing rads are that sludged up power flushing them will make one or more of them leak and once one starts the others won't be far behind. I think I'd be looking to flush then replace myself.

I did it like chippy (all the sludge in mine was in the lower sections of the pipework/rads). When I fernoxed it after, the downstairs circuit stopped working until I drained it down again (due to dislodged sludge). Refilled again and all ok - total cost was about £40 for fernox and inhibitor. #

The sludge in mine was horrible black stuff that stained everything it touched, so make sure you get some thick polythene sheet down when disconnecting the rads/dragging them outside, cos if there sludged up they may not fully drain until you start moving them around.
Regards
Hugh

Would it be better to remove the radiators and replace them with a piece of pipe and then flush and then replace the rads. This would get rid of all the sludge in the rads and you would only have to flush the pipework and the boiler. You could probably do this with a garden hose or similar and save a lot of money on a power flush.

Just to add a comment, when I did mine I was told by a heating guy that copper pipework didn't make the sludge, it was made by the steel of the radiators and "usually" was restricted to being mainly within them, and as it sunk down to the lowest point which is below the valves would remain within the radiators as a general rule. As I said it worked for me so must be something in it in the way of truth. Cheers Ray

I too have been told about hosing rads out. Seems a good step to take as cheap and pretty easy. A good flush with a decent cleanser and a bit of re-flushing. Probably be near enough as good as a powerflush.

In systems that have a combi, I have used a "magnaclean" after having a new heat exchanger due to clogging. They catch a vast amount of stuff in a dirty system, but in mine at home that was all new, clean as a whistle after 5 years (fernox inhibitor)

I had to drain them to replace the pump a year or so ago, and I just stuck a piece of hose to the drain pipe at the bottom and chucked the other end outside.. A load of black water came out, but I get the feeling it could be a simple case of do that, rinse and repeat as needed