Cold Radiators?

Turn the hot rads off and the water pressure may force the others to warm up. hope this helps Juliexxxxx

Sounds more like poor circulation.

If your radiator valves are ok as suggested before and you have just turned the heating on after some time the problem may be the main circulating pump (or a heating divertor valve). They may be sticking or sludged up. Does the system sound "mechanically" noisy.

You could try to free the pump by switching the room thermostat on and off a few times in succession.

Good luck

Check the valves are open, if so, turn off the hot radiators, when the heat starts to circulate, turn the others back on a bit at a time, when they start to get hat again, they are open enough, do this gradually with time intervals between turning back on, if you open them too much when you put them back on, they will take the heat away from the others again. The other thing to try is, if they are thermostatic valves, remove the heads and tap the pin underneath, they may be stuck. when you have done these, you may want to organise a power flush, British Gas charge £600+ everyone else is cheaper.

If you have the older type of thermostatic radiator valves fitted they some times stick shut if closed for long periods.You will have to drain down and fit new valves. Also check that the pump is running and has not ceased up through lack of use thoughout the summer.

If you havent used the system for some time, you probably have an 'air lock'. turn off all the rads that are working, leaving just the cold ones on. this should move the air back up the expansion pipe. good luck.

Check that both valves at the bottom of the rads are open!

You can turn these with pliers. (Gently). If they are all open and no air is coming out when you bleed, you must have a blockage somewhere in the system.

If you have thermostatic valves, remove the head and then gently move the pin underneath with a pair of pliers, push it down and see if it springs back up, apply a small amount of Vaseline to the pin to prevent it sticking again.

Are the valves open on the cold rads. Is the cenral heating pump working okay? If you have a Combi boiler, is the water pressure okay?

Check the valve at the bottom to make sure they are fully swithched on. If you can feel the pipes are hot up to the valves then the valves are shut, just open them.

you need to bleed them in the right order and make sure all valves are openstart with the radiator furthest from hot water tank downstairs first