central heating problem

[PP]

Hi Why does a central heating radiator heat up when the heating is switched off at the boiler but the hot water taps are run? Any suggestions please? TIA Phil

[Don Spumey]

My bathroom rad does the same. It's the nearest in line to the boiler & the heat radiates to it when the boiler kicks in to provide hot water.

Don.

[EricP]

What sort of system are you talking about?

Combi, gravity, pumped??

[PP]

Combi. It's an old boiler (Myson Midas), and two radiators have stopped working. I think they may be blocked.

[biggirlsblouse]

A common problem caused by thermo syphon currents which is eliminated by the installation of a flap valve in the central heating pipework feed. The flap stays shut preventing thermo syphon currents but when the pump is started it has enough power to move it to the open position