On the heat pump side of things I built a data logger and the awuful graph shows the data from 10/12/2017 to 13/12/2017, in the 3 days outside was around zero degrees the heap pump did 10 heating cycles and 5 hot Water cycles.
At zero outside the heating flow temperature was 35 degrees sub zero (issue with the data logger not logging negative numbers) the flow peaked at 37 degrees. There is no inside temperature compensation which would have helped maintain the inside temperature be a bit more consistantly. The heat pump on heating is running for 1.5 to 2 hours at a time, gound temperature is 7 degrees.DHW temp was set to 48 degrees.
What you can see is that the Detla T on the heating flow and return is about 6 degrees. This is mainly the upstairs UFH, due to bugdet I did not install spreader plates which has 2 neative affects, the upsatairs room temperatures was slightly lower and the return temp from the ufh was higher, I tried to compenate with exta pipe but spreader plates or a sand bed would have been better. the other option was to add a heating coil to the MVHR which was the ducting had been fitted for.
