Hi all,

I have noticed something with my boiler that seems strange to me, but
I don't know a lot about heating so I'm not sure if it's actually a
fault.

It's a Worcester combi boiler, and when I run a hot tap for a while
(say for a shower) the radiators get warm; this is with the heating
turned off! They don't get red hot to the level they would with the
heating turned on, and the 'heating on' light on the boiler doesn't
come on, but they do get quite warm to the touch as if they have
heated water inside.

From my limited understanding the water in the radiators is in a
closed loop whilst the tap water is coming from the mains (I don't
have any water storage tanks), I can't really see how or why running a
hot tap would heat the rads?

Then again this may be normal, I don't know! I've only ever dealt with
two boilers!

I would be grateful for any advice,

Thanks,

Ian.