Central Heating

[Mercedes7Astra]

I've moved into a house that was origanlly 8mm piping to the radiators, some have been converted to 15mm, the problem is that some of the radiators are not getting hot particularly the ones that have been converted, they are all on the groundfloor. I have tried to balance them but no luck.

The bottoms of the radiators are cold the tops are warm, I've tried bleeding the system, it's been power flushed, what else can I do!

Any suggestions please.

 

[D_Hailsham]

The bottoms of the radiators are cold the tops are warm, ... it's been power flushed

That means it was not power flushed properly as the the rads are still sludged up. You can either get the chap back again and insist he does the job properly or, and this may be less hassle , remove the rad and flush it through with the hose, giving it a good thumping with a rubber hammer or similar, to dislodge the sludge.

It also sounds as if your system is still not properly balanced. The rads on 15mm will need their lockshield valves virtually closed, say 1/4 to 1/2 turn open at max.