Decrease burner power before lowering target flow temperature
Hi,
I have a bosch condens 2500 boiler, connected with nefit opentherm-ems converter. Using this setup with tado x wireless receiver (+trvs, wireless thermostats), via opentherm control. As far as I see, this setup works well, changing the target flow temeprature and setting the burner power to minimum value happens, so the control is good.
My issue is that this boiler allows only a 1.1-1.2°C tolerance regarding the target flow and current flow temperature. When the current flow temperature rises, the boiler modulates well, and the target is only exceeded at a maximum of 0.3°C. But, when the target flow temperature is decreased (even only 1 °C), the difference may become too big, hence the heating is stopped, only the pump runs. And after the configured delay, the burner starts again. This whole behaviour causes unnecessary burner starts, which should be avoided.
Please note, I'm aware that this is an issue with the boiler, but I have no means to change it's behaviour regarding this, also won't change the boiler itself just because of this.
What I would like that tado should handle this situation. One simple idea, that wouldn't hurt (even generally, or via a configurable option):
1, when the target flow temperature needs to be decreased, first the allowed maximum burner power should be set to minimum value.
2, Wait for the flow temperature to decrease to the target temperature (probably with some little timeout, it may happen that low temperature cannot be reached after all)
3, change the target flow temperature to the desired value
4, set back the burner max power to the value which was before this while procedure
Or any other solution is welcome, which solved the original issue.
Thank you