As per the title. I've fitted a heated towel rail (duel fuel) in place of the bathroom radiator. It's quite a tall one, much higher than the previous rad, but it filled up with no problems. I've bled all of the rads, there is still a slight gurgling from the pump but nothing excessive. I've got no heat in any of the downstairs ones - not even slightly warm. All of the upstairs ones are really hot.
The water was relatively clean so I don't think anything's sludged up.
Have I upset the balance somehow? I've tried turning the towel rail off completely but that makes no difference.
Or have I got an airlock? I've drained/refilled the system before and didn't have any airlock problems then.
TIA