i have a single pipe loop system i moved a radiator and it will not heat at the bottom

simon johnson, February 2007

If you have a dual valve head at one end of the radiator, you may find that the internal injector tube has come adrift, this will give poor circulation within the rad.

Pete, February 2007

nether mind air in system.... its as earlier, sludge in system, this causes the TRV too stick or no flow throw the TRV too lockhield. .............

close both down and drain and remove rad, flush rad with hose pipe and replace, open valves, lockshield same number of turns it took to close, check system pressure at boiler and increase to a little above 1bar (1.2/1.4). run heating this should be ok.

system may need a full flush dead easy, if in doubt post again..
CLFGAS

clfgas, February 2007

cold rads at bottom indicates sludge in the bottom of rad.

hi-spec plumbing, February 2007

More than likely still have air trapped inside the radiator. With the circulation pump running, undo the radiator bleed screw. You shoul hear air escaping along with some of the water. Be careful as the water will be hot and you could hurt yourself. Keep doing this process over a number of times. Eventually all the radiator will come good.

DaveL, February 2007