Compensation curve settings when using an Ecodan Air Source Heat Pump with under floor heating

  • 8 July 2022
  • 5 replies

Userlevel 4
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Hi all,


Turns out one of my neighbours has the same econdan heatpump as me. However he is getting much worse efficiency. Annual COP of 2.2 vs mine of 3.0. I checked all the simple settings and it all looks fine. The only difference is that he has underfloor heating, where as I have radiators. Wondering if anyone know is there is a different setting for underfloor heating?

many thanks



5 replies

Userlevel 7
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You know heat pumps are becoming popular when your neighbour has the same one as you! 😁

I would have thought that underfloor heating would help with the CoP.

Have you compared flow rates? This may impact on efficiency.

Maybe theirs is cycling on/off more than yours?

Userlevel 4
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James your neighbour should be running their UFH at 30-35° and getting SCOP nearer 4.

Are they trying to run the ASHP like a boiler, E.g. on/off with a thermostat or running 24/7 only using weather comp? The latter is what they should be using, regardless of system emitter type.

Userlevel 5
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On the Daikin system you do set an emitter type, quick for radiators, slow for underfloor heating. This alters the way the heat pump behaves. 

As Jason said, I’d also expect the leaving water temperature and weather dependant curve to be much lower than in your system. The max. leaving water temperature on an underfloor system my father-in-law has is 35C at -2C outside, whereas on mine it’s 42C (reduced from the 50C set by the installers). 

Userlevel 4
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Thanks for the replies. they are running it as you would expect, on all the time and on a thermostat. I think they need to get the installer back in!

Userlevel 4
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On all the time good, thermostat bad. 
Thermostat needs to be set high (say to a “just too warm” to be comfortable setting) and experiment with weather curve to give the actual desired temp. Can only really do that experimentation in the winter.

That should reduce cycling which is the enemy of the heat pump. It is worth asking how many cycles per hour are showing on the controller as that gives a good idea on the cause of poor efficiency.