@matt-drummer Hi Matt, this one is mine.
I use Leaving Water Control (aka pure weather compensation).
I have dT set to 5C target
Set to Sample and also Pump limitation for sampling at 60%
I have very narrow curve (32C @ 15 & 38C @ -3C) as it seems happiest in this range.
I have disabled the boost it does around 0C
I have disabled all backup and booster heaters
Auto bypass valve fully closed
Open system.
In fact I have tried reinstating the Honeywell controls to load shift using the UFH, and can see that it save no input electrical power, just outputs less heat!!! So UFH is now back to fully open, no valves, no pumps, no controls. Just old fashioned balancing.
Importantly, I have overshoot at its max of 4C - today a perfect example as most of the day it has run just over the target flow temp by a degree or two, and if I hadn’t got the 4C overshoot enabled, it would cycle like mad.
This unit appears to be most efficient running at minimum output (with the caveat that it needs the emitter output to be able to take the heat and dissipate it)
I think the madoka + its modulation may be your issue at this point as I use neither and you have significantly upgraded the heat output/load now