Can I turn heating on after draining a radiator?

[BelfastSmile]

Woke up this morning to a leaking radiator. Water seems to be coming from the nut near the temperature-control valve.

So, I found instructions online to stop the leak - turned the temperature thing to as low as possible, then used a spanner to turn the valve thing at the other end of the radiator. Then bled the radiator until water stopped coming from the bleed valve.

So now the leak has stopped, presumably because there's no water in the radiator. I'll call a plumber in the morning (boiler needs serviced anyway, so he might as well do it while he's here).

Can I turn the heating on in the meantime, or will the water not circulate? Would it be dangerous? I can't find anything online.

eh? You emptied a radiator via the bleed valve?! thats not possible without emptying the system which would take days through a bleed valve.
It sounds as though you have tightened the nut and stopped the leak and bled the air out (not water) and isolated that rad. Should be fine to turn heating on

Yeah, I didn't empty it, just let enough water out to stop the leak! Thanks for the advice, good to know I can turn the heating on.

Best thing to do is check your system pressure first. If it is at 0 bar, make sure that you top it up to 1 bar, before you turn your system back on. Otherwise, you can cause problems to your pump and boiler. If you have a tank in the loft that feeds water into the system, you won't need to do any of that, though it would be a good idea to bleed all your radiators.

Thanks, @Muchlywrong - the boiler pressure is sitting at about 1.

Hope you've managed to find a plumber. Meanwhile hope it's not too late, you can turn on the heating and it won't be dangerous.