Rads slow to heat - bigger pump required ?

[yoda]

Dropped the boiler output to 24kW and it runs for much longer, plus more heat appears to get into the rads overall.

There's still the issue that those rads closest to the boiler get hottest (and quickest) so I suspect that the system would benefit from proper balancing but, other than that, I'd have to say that its looking encouraging so far..

 

[D_Hailsham]

Dropped the boiler output to 24kW and it runs for much longer, plus more heat appears to get into the rads overall.

That's encouraging! I would still work out the heat output from the rads - using Stelrad Catalogue or the quick way - and compare this with the 24kW you currently have the boiler set to as you may be able to reduce it even further.

I suspect that the system would benefit from proper balancing

That sounds a good idea. You can find info on balancing in the FAQs or I have given detailed instructions in other posts. See //www.diynot.com/forums/viewtopic.php?p=1068597#1068597