It does just seem to be what the smaller Daikin units do, especially at lower power input levels.
Its the input power which varies, which in turn causes the LWT to fluctuate. You never see the variation on the RWT because the water becomes too mixed as it moves around the central heating circuit.
I have a theory that the compressor speed (or input power maybe) is variable, but in fixed increments. When the input power fluctuates between two levels it is achieving an average power between its two fixed power levels by pulse width modulating between them, but that is just a theory.
COP is generally good so it just appears to be how they work. If you didnāt have monitoring you would never notice it.
Well exactly the same on my Samsung and I canāt figure it out. Seems really it starts when LWT reaches the target temperature and DT canāt be maintained anymore because Iām at lowest flow temp already. Compressor jumps from 22Hz to 14Hz and back every minute. I simply donāt understand why the pump canāt modulate much more smoothly. It happens more when itās warmer outside and compressor is already running at low power. Iāve found enabling compressor frequency control help prolong this interval until it starts flutter but itās only because the pump will start heat slowly. Seems for radiators with low water volume itās a problem but matt mentioned he has over 300L in the system and still has these flutters. So I donāt know but itās driving me nuts.
