by plumbbob »
Thu Dec 02, 2010 11:13 pm
dockinnley wrote:Ihave had new radiators installed throughout our house and recently my wife noticed that some of them are colder at the bottom than at the top, I assumed the problem could be cured by bleeding but this has not helped/ I have been told that the setting of the lockshield valve may be the problem. Any advice would be appreciated
Hot water rises as it enters the radiator so a cold top means trapped air and a cold bottom indicates poor flow.
The most common problem is poor balancing.
Find the hottest radiators in the house and turn the lockshield off totally then open back up one full turn. Give the system 15 - 30 mins to settle and repeat the procedure but only alter the LS by a quarter turn.
If the rad is red hot, shut it down,. If it runs cool open it up. Eventually you should end up with an even flow of hot water through each rad.
Incidentally, if you have an open vented system check the pump speed and ensure the cylinder bypass is not fully open. Also, ensure any system bypass is not open too far.
