Flushing Radiator

AlwaysSomething

I got a new boiler and radiators two years ago using the old piping. There is a sticker on the boiler saying that it is filled with cleaner and inhibitor (X100 and X300?). However, a downstairs radiator is now cold on the bottom, so I guess it's full of sludge. I think I am up to removing, back-flushing, and replacing the radiator, but I'm concerned about the effect on all the additive levels. Should I:
1. Back-flush the rad, then refill the system with water
2. Can I top up the additives?
3. Back-flush, but drain and refill the whole system using new additive
4. Call a plumber?

bockster

personally i would use new cleaner and inhibitor at least every two years.
this would involve draing from the lowest points in the system, and is a good time to remove, if you are able, and flush any rads.
bear in mind that the pipework could be clogged up as well as rads.
me, i would flush rads in the garden, refit, refill with cleaner then see what the result is before draining again and filling with inhibitor. to be honest , a powerflush would be the ultimate solution to a clogged system, but this is , after all, a money saving site.
hope this is of some help.

27col

If you are only going to drain one radiator, then there is no real need to renew the inhibitor. You will only lose a small amount of the total in the system. I cannot see why a newish system should be having trouble with sludge in the radiators. Any way, delay putting any more inhibitor in until you are sure there are no more problems with the water circulation.