So,
I wouldn’t have seen the below without heatpump monitor. It hasn’t done this before (minor fluctuations - nothing this erratic). I’ve bled the system on the buffer tank, very little air came out and the system remained at the same pressure on the gauge.
That’s about it for my knowledge of what to do.
So any thoughts appreciated.
This is from early on in the day
This is something that has been seen on some heatpumps…
…though those typically see a matching oscillation of the electrical input at the same time. That makes me wonder if the fluctuations are real, or some noise on the flow temperature sensor.
What model of heat pump have you got, and how is performance being measured?
Interesting. I would except your power input erratic as well. To me it looks like some flow temperature sensor issue. On my pump I have this pattern when flow temp is reached and the pump is not able to maintain it properly for some reason. But then power input is jumping easily by 300W. I believe it’s some bug in controlling firmware because there is no reason why compressor oscillates between 22Hz and 14Hz all the time instead of 22 - 20 - 21 - 22 or such for example.
@Timbones I have an Acond Pro-N unit. Monitoring wise I have SDM120 Modbus/MBUS Single Phase (class 1) and Sontex heat meter (class 2)
@Michal_S I’ve had the unit for a few years now and this is the first time I’ve noticed it, it will go as low as 460w usage. It has always been steady though without fluctuations.
It’s last run is now back to normal.
Thanks for your replies.
Yeah, it’s strange so good it’s back to normal. I wish I have such a graph as you have 
I got mine from Level 3 Heat Pump Monitoring Bundle (emonHP) - Shop | OpenEnergyMonitor Now half the price I paid, well worth it though.
