I have a conventional GCH system, not a combi. The boiler is working and as far as I know, so is the pump. I should say that the pump is upstairs and the boiler downstairs. The house was built in the 80s and the pump has been replaced in the last ten years. The downstairs rads are always cooler than upstairs. Recently I turned off the heating while away for a bit and when I turned it on the downstairs rads wouldn't heat beyond tepid.
Hot water isn't a problem.
Decided to balance the system (without thermometers!).
Opened all lockshield valves up and downstairs and also the handwheel valves. Now downstairs completely freezing and upstairs boiling. I am thinking of turning off all the lockshield valves upstairs to force heat into downstairs. Is that wrong? Should I just turn off some rads upstairs with the handwheel and leave the LSVs open somewhat. A couple downstairs never come on at all and the pipework is cold either side so I've left the handwheels and valves off on these.
Thanks for your help.