Switch on Hot water & radiator also getting warm

ran123ran_2

Recently realised that when hot water is switched on, the radiator nearest the hotwater tank & boiler also starts to get warm.

Had heating installed last October and this fault has only become apparent. Last week BG came and replaced a valve to fix the problem. The fault was still not fixed. BG came out again today and have advised that when heating was installed the return pipe in the water circuit is connected to the return pipe for heating.

Hes coming back tomorrow to redo the pipe work as he had to order pipes. (I just expected them to carry some legnth of pipe with them?).

I have no knowlwdge of heating/hot water systems but what concerns me is that if water from hot water circuit is heating up my radiator, then is my hot water being contaminated with water from radiators?

I am really worried about this and have been advised by BG engineer that it isn't getting mixed - but then I can't understand how the hotwater from tank is heating up radiator?

Can someone please advise?

gas4you

No.

No chance of any contamination as the heating water and hot tap water never mix.

The hot water from the tank isn't heating your radiators. It is the heated water from the boiler, going around the hot water cylinder circuit that is reverse flowing up the return to the radiators. Your hot water cylinder has a copper coil in it that this heated water goes through to indirectly heat your hot tap water, hence the term 'indirect cylinder'.

Quite a common problem when both returns are not taken back to a common point and piped up correctly.

Pincher

I had specifically told my plumber I wanted the towel radiators in the bathroom on normal radiator heat circuit, as opposed to the hot water cylinder circuit, which was on a Y-Plan before the renovations.

Now that we are on S-Plan with separate zone valves, he still put the towel radiator on the hot water circuit! Because that's how he always did it! This meant cold bathroom during the winter seven months ago, because I only heat the water once a day around 4am. Had to get him to do it again.:(