Sunday Express Skeleton 24Th November...
Crosswords7 mins ago
No best answer has yet been selected by Jackson74. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.Jackson, If, following the good advice offered previously, ( done when the pump is off, by the way ), you find that there is only water , and no air, a air - lock may not be the problem.It is unusual for air to cause a radiator not to heat up " all of a sudden "as you say, it is more of a gradual fault, i.e. only a small part of the top of the radiator not hot at first, then the cold spot gets bigger gradually.
Hope the bleeding of the radiator does work, but if not, come back on.
One other bit of advice that I can offer (from experience) is.. Be patient when 'bleeding' radiators. The screw in the middle of the bleed valve only needs to be open a small amount to be able to release the air. Try wiggling the screw a little (sometimes they can trap sediment/sludge). Don't remove it completely. It can take longer that you would think to screw it back in when rusty water is spraying down your wall.
Another tip.. Turn off all the other radiators. If the problem radiator heats when the heater and pump are running.. Then it can't be 'airlocked'. But listen for bubbles running through it.