Hi all
I'm a total beginner when it comes to anything like this but have tried reading up in a DIY manual plus read the uk.diy faq and have attempted a little investigation today.
Six radiators in the flat. All but one heat up quickly (within a few minutes). Furthest from boiler (24kW) only gets a bit warm at the top even after central heating has been blasting away for fifteen minutes.
So, just to limber up, I've increased the pressure when the system is cold to 1.2 (it was 0.8).
When it's on, rises to 1.4. From what I've read, this is about right.
Also attempted to bleed the radiators but there is absolutely no air in any of them as water spurts out immediately.
Took 1/2 pint sample of water from nearest radiator and furthest one. Sample water looks the same - a few little black specks but a clear, yellowy colour which I presume comes from the corrosion inhibitor (the boiler was installed 2000) - is it the inhibitor? I'm going to put a nail in once I get hold of one (don't laugh!) to see if it rusts compared with one in tap water.
So far, is there anything untoward? Does the clear water indicate that the faulty radiator is OK or can this single radiator be suffering from corrosion?
Next bit. When the boiler was on for ages the cold radiator's 'in' pipe got extremely hot but the 'return' pipe (and most of the radiator) stayed cold. What does this suggest?
Also, I really turned the thermostat up full but found that the boiler would switch off after fifteen minutes. The idea was to see if the faulty radiator would actually heat up eventually. The thermostat is in the kitchen (which is where the boiler is, where the best radiator is and of course the hottest room in the house) - is the thermometer it uses in the same place? Would that explain why the boiler turned off too quickly (i.e. with the faulty radiator in furthest away bedroom still cold)?
I was intending to start opening/closing valves (and ultimately leading to following the 'balancing' instructions) but *all* the valves on every radiator have no covers and they look identical at each end. So, I can't tell if each valve is a thermostatic radiator valve, just an on/off valve, lockshield valve for balancing etc etc! Any ideas how can I make progress?!
Another thing, I am not sure if the central heating is a 'one pipe system'. Does this make any difference w.r.t identifying which valves to fiddle with?
One more question. Quite alot of the valves are a bit corroded/mucky.
the system must be emptied. All the valves could do with replacing but is this that sort of thing 'worth it' - it seems emptying and filling is quite a big proposition?
Oh dear - it's all a bit of a learning curve! Sorry it's so one-sided :-(
Emma