Weather compensation curve on ecodan - what's happening at the right-hand end? - Air Source Heat Pumps (ASHPs) https://renewableheatinghub.co.uk/forums/renewable-heating-air-source-heap-pumps-ashps/weather-compensation-curve-on-ecodan-whats-happening-at-the-right-hand-end/ Questions and discussions about renewable heating and heat pumps en-GB Tue, 17 Mar 2026 03:25:51 +0000 wpForo 60 Weather compensation curve on ecodan - what's happening at the right-hand end? https://renewableheatinghub.co.uk/forums/renewable-heating-air-source-heap-pumps-ashps/weather-compensation-curve-on-ecodan-whats-happening-at-the-right-hand-end/#post-21601 Tue, 19 Sep 2023 22:34:59 +0000 It makes sense that at the cold set point on the curve, you choose a max flow temp and at colder outdoor temps the flow temp stays at that level. But what happens at the warm end? If it followed the same logic it would keep heating with the minimum flow temp even if the  ambient temp is 25C. I observed the system (when warm outside so no heating needed) raising the flow temp to the minimum, then stopping the recirc pump and only heating the water again when the thermistor reading dropped below a certain offset (despite no circulation!). Bizarre.

I know I can just turn the system off and I have now put it in 'summer' mode where it waits for a certain duration of cold before turning on. I would just like to understand better the 'why'. Surely the curve should just finish at the upper set point rather than having the plateau on the RHS? Am I missing something?

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]]> Air Source Heat Pumps (ASHPs) Tinkerer https://renewableheatinghub.co.uk/forums/renewable-heating-air-source-heap-pumps-ashps/weather-compensation-curve-on-ecodan-whats-happening-at-the-right-hand-end/#post-21601