JimK wrote:

IME heat outputs are minefields - all depends on temp of water in them
- these days outputs should really state "at delta T 50" but some
still state figs calc'ed using "delta T 60" which makes comparison
difficult - search back through UK.DIY (if you can) and try to find a
better explanantion - you can also convert from one delta calc. method
to the other but I forget how....

JimK

Delta against what? Flow-return or water-air? It sounds a lot either
way - I thought we were supposed to be heading for flow 50, return 40,
room 20 these days.

Andy