Combi and sealed system draining. Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[steve970uk]

I have a Worcester 28CDi and I believe, a sealed system. I had a downstairs rad that was cool and was advised to close the TRV's on the surrounding rads to try to force any debris past the blocked rad. I did this....and now have a cold upstairs rad! I can't unblock this by closing any valves and am guessing that I need to flush the system. Is this viable for a DIYer and if so, any tips on how to do it.
Thanks in advance.

[gasmick]

hi it could be just the pin sticking on the trv, try removing the head and try tapping the pin with a pair of pliers and see if it comes out a bit more
remove 1 other and see how far the pin is out on that one they do have a tendancy to stick down when closed manually

[steve970uk]

Thanks, that worked a treat. However the downstairs rad is now unevenly hot with some cold spots at the bottom. Is this likely to a circulation problem or a build up of sludge. Thanks again for your time.

[gasmick]

hi well it looks like its time for a system flushing as you have described cold at the bottom are just the symptoms of the black death as i call it so a power flush is the thing to do as it does use a reversing action pump and uses chemicals then inhibitors can be put in so make your sytem last another 10 years or so or you will soon be having to start replacing rads as they rot away from the inside though electrolosis
Its not cheap to have done but its well worth it in the long run as it will save the boiler glogging up as well

mick