Spot on Trystan. It’s worth pointing out that my radiator capacity (including 4 convectors) is 12 to 13 kw at a mean flow/return of 40c so the system is not emitter constrained. My house was definitely getting warmer last night with around 8.5kw input at about 1c so it is close to my ‘design’ capacity requirement of 9.8kw at -2c… which the Daikin data book says it should deliver. Grrr!
This evening with the same outside temperatures I am pushing it less hard - just 6.8kw and the COP has recovered from 2.3 to 2.9 along with larger intervals between defrosts.
I am still puzzling over the tech data Daikin supply - two pages after the capacity graph in the post above comes this table with wildly different capacity values and COPs for the same machine.
I took the MCS number and the graph as accurate when dealing with Daikin but now wonder what these other test standard results really mean. Do the other brands produce a similar tables to this?