by htg engineer »
Sun Jul 11, 2010 9:40 pm
Sound like kettling, the pipes may be abit furred up - limescale etc. With the heating on - the pump runs - so some heat is taken away for the radiators - the rest will be forced round the primaries.
You could try adding a cleanser/descaler, replace pipework etc.
But if you have a limescale/sludge/debri build up, it'll be in the heatex, tank/cylinder coil. Best bet would be to put you money towards a new system, instead of trying and possibly failing to rectify problems on your current system.
However as long as your water isn't too hot - boiler stat is working correctly. It may be a nuisance - but it's not dangerous, if you can live with it - it gives you time to save for an upgrade.
htg