paulfoel wrote:
Very strange.

Got a heating controller that, basically, you set separate times from heating and water.

At the moment, heating is off. But we still need hot water.

Trouble is radiators still come on even when its off. (But obviously, boiler is running heating the water).

Any ideas?

Not knowing much about it but I assume that in this case something should be telling the system to fire up, heat the water but not send hot water into the rads?

I suspect that you possibly don't know if you have S plan or Y plan
system. If you have a single motorised valve with three pipes going to
it, you have Y plan and the valve is probably stuck or the motor has failed.
S plan has two (or more valves) each with two pipes. One will be for hot
water and is probably working OK but the heating one (or more) is stuck
open. This is not likely to be a motor failure as the motor opens it and
a spring closes it. Most likely a stuck valve.