Lukewarm radiator....help needed

[giw12]

Would really appreciate some assistance on a lukewarm radiator. It gets warmish at the top but is barely warm at the bottom even though the thermostatic valve is at maximum. The flow pipe is red hot but the return is barely warm.
All the other radiators are OK.
I've bled all the radiators but there was very little air in there.

Friends and family have come up with:
1. Sludge (but the whole system was only put in 7 years ago)
2. Dodgy valve

Any advice on how I identify/eliminate the problem?

Ta.

[Silverbullet767]

Sludge at the bottom of the radiator, you need a power flush.

[giw12]

Flush just the offending radiator or the whole system?

[igiveup]

Powerflush = expensive.

Try this first. Turn of valves & Remove offending radiator, don't forget to catch/drain the radiator into a bucket or bowl (plenty of old towels at the ready). Flush it through with hose in garden. Put radiator back on. Fill system (add a bottle **"Sentinel X400 Central Heating Sludge Remover" (about £13) via header tank or radiator, leave for 2 weeks, drain whole system then refill adding **"Sentinel X100 Central Heating Scale Inhibitor 1Ltr". If this does not sort it then a powerflush it will be. You have only wasted £13 or so then.

Thats what I would and have done in the past.

• Other product brands avaliable.

[Ferg]

V8mate said:

Did you get your radiator sorted?

Be interesting to know, because I wouldn't say that was a sludge issue.