Following the exchange between @dfeist , @Zarch and me in the Vaillant owners Thread, here’s some comparison data:
My system
Roughly a 1.2K constant offset between flow & return. This massively overstates heat generated in the Vaillant stats. My own (non MID, but properly calibrated together in an ice bath & sous vide) sensors work as expected.
@dfeist system
A 0.3K offset between flow & return but in the opposite direction than for my system, leading to an underestimation of delivered heat and thus COP. Heatmeter sensors work fine as flow&return are identical between cycles.
@Zarch system
Difference between Heat Meter and Ebus
- Flow: around 0.3 & 0.4
- Return: around 0.4 & 0.5
This would work out to a constant delta of around 0.1-0.2. Just from eyeballing it appears Vaillant would also slightly underestimate here.
If anyone else wants to contribute a similar graph I’d be happy to add it to the post.
@Zarch , @dfeist : If you don’t mind - could you also provide a snapshot of how flow rate compares for reference?