Hi Ali,
Thanks for the reply.
I’m glad you avoided the 9kW, good work!
All of these 4/6/8kW heat pumps preheat the compressor, even when short cycling.
Look at any of them, mine or Zaks as they are MID metered just to be sure.
You will see electricity consumption every time before heat is produced, yours goes straight to heating.
Your heat pump will be preheating, they all do, something is wrong.
So you had 7,556w of radiators, I guess from your radiator schedule from Octopus?
If so that will be at dT30c, that’s about 15kw at dT50c and maybe with your upgrades, maximum 20kw.
That is less than Zak has, I think he has about 30kW and I have about 50kW.
Is a lot of your lengthy pipework outside?
It shouldn’t affect your dT and therefore your heat production data but it might explain where the heat is going?
You have your dT set to 3c on ufh?
From your current data your dT between flow and return is about 5c
Octopus normally set the emitters to fan coils, you changed it?
I think I am starting to understand.
At times the data looks quite reasonable, in line with mine, a heat loss of around 5kW and with what I would have assumed were large radiators.
But it didn’t make sense when it was colder or warmer, then it gets very different to me.
Something isn’t right with the data if you have it set at a dT of 3c an you are showing 5c.
And it may be that a lot of your heat is not reaching the house?
That would explain how you can run continuously when it’s warmer and the rest of us can’t and why your performance drops when it is cooler.
I think you need to do some checking.
Not to satisfy me or anybody else but I suspect your efficiency is nothing like you are showing.
If your radiators are about what I said there is no way your data is correct.
I have never seen Octopus fit enough radiators, they always design to 50c at -3c.
I only have what I have because I changed them all to make my 9kW work.
I had about 18kW of radiators post install, about the same as you.
Zak was the same and convinced them to go bigger when his heat pump was changed.
I did mine myself as I really wanted to make the 9kW work, and I really did try!
Your house is bigger than mine and Zaks so your heat loss may well be a bt higher.
I am heating an all glass conservatory though which is a bit of a problem at times, but does effectively make my house a bit bigger and closer to yours because of the heat loss.
I think you need to check our electricity and your dT.
If you can it would be useful to check the dT where the flow and return enter the house.