Is replacing one radiator a solution?

[diy_fun_uk]

I have an old central heating system powered by an Ideal Mexico boiler. There are 7 x radiators, 5 x single panel, 1 x double panel, 1 x bathroom towel radiator. All on the same level (bungalow.) All of the radiators are fed by what looks like 8mm pipes except for the double panel which looks like 15mm. This one is in my lounge area and is the largest at 160x45cm.

When the boiler comes on, I usually get a gritty / swirling water noise from the double panel. It's getting worse as the years go by and can be quite annoying as it happens each time the boiler comes back on. When I bleed it, the water is black so obviously the system has bits of rust and sludge in it. There are however no cold spots on the radiator, actually all of them don't seem to have any cold spots and they all reach a good surface temp. All the other radiators used to bleed clear water up until a few months back, now all are varying degrees of black except for the bathroom.

Weirdly, the only radiator that makes a noise like this is the double panel, the rest are silent.

I know the normal course of action would be to get the system flushed, however I've also read this doesn't always resolve the issue first or even second time round. I'm wondering, if most of the rust and sludge is concentrated in the double panel radiator, might I be better getting this replaced rather than go down the flush route? I'm also slightly concerned with it being an older installation that the flush might cause more issues than it resolves?

Thoughts and advice from those in the know would be welcome

 

[terryplumb]

Do you have a magnetic filter ? If not, have one fitted.
Remove the d/ panel rad ,take it outside and manually flush it with a hose pipe. Whilst it is off the wall check the valves for any build up of crud ,open each in turn and let water flow out for several seconds.
Re fit rad and see if any improvement.

 

[MeldrewsMate]

I concur with Terry.
Also you may wish to check that the small loft tank (if an open vented system) is not getting warm, or pumping over when the heating is running. If it is then you must cure this to stop the system corroding further (pumping over causes the system water to entrain air, and sucking down causes air to be pulled into the system each time the pump starts).

For better advice consider describing your system, with or without photos.

 

[diy_fun_uk]

Thanks for the replies, I'm pretty sure my system is open vented however will venture into the loft space in the coming days and take some pics.