Is an oversized Daikin really a problem?

[divenal (Dave Denholm)]

@Mld

Looking at it, I think the Madoka modulation steps are occurring at 0.5C over the room thermostat target for each step. So after the first step, if it’s still 0.5C over the room target some time after the first step then it applies the second step.

Am not 100% sure but it looks like this is what’s happening.

I saw another thread somewhere which confirms this: once the room temperature falls below target by 0.5 degrees, it applies 1/4 of the modulation value (2.5 for you). Then if it falls by another 0.5 degrees, it applies another 1/4.

Daikin Monobloc Heat Pump - User guide

Indeed modulation varies LWT, though with a rather simple algorithm, at least for my older hybrid, but I think it might apply to the monobloc too: -if the room is too warm for more than 20 minutes, the LWT setpoint is lowered by 1 step size (which is 25% of the max modulation setting [9-06] which is default 5C (max 10C), so default step size is 1.25C), -after another 20 minutes of the room being too warm, LWT setpoint is lowered by 2 step sizes, -until the room temperature goes below RT setpo…

I use modulation of 4, so 1 degree change to LWT for each 0.5 degree error. For the most part, this then gives just enough negative feedback to keep the room at 0.5 degrees below the target temperature (19.5 degrees with a target of 20 - when it drops below, LWT gets increased, and when it reaches 19.5, LWT reduces again).