Feature request for a user defined allowed overshoot above room setpoint

[Edwin184]

Dear Diyless, I'm using your Diyless thermostat but ran into a conflict between the algoritm used by the Diyless and my heatpump.

I have a Quatt heatpump that works based on room temperature. Based on the current room temperature and room setpoint my heatpump uses its own PI algoritm to calculate the water setpoint. My heatpump ignores the water setpoint calculated by the Diyless and aims to use the overshoot to lower its heat output to get back to the room setpoint.

Problem description: The behaviour of the Diyless is that the Diyless sents both the water setpoint and the room temperature to the heatpump. So below reaching the room setpoint everything works fine as my heatpump can use its own PI algotitm. However when the room setpoint is reached the Diyless puts the heatpump in idle mode and waits until the overshoot is done and starts the heatpump again when the room temperature is back below the room setpoint. This results for my heatpump in an increasing number of stop/starts (which is bad for its lifecycle) caused by the Diyless forcing idle mode but also breaks the PI algoritm of the heatpump. So its makes my heatpump less efficient.

Feature request: So my feature request is whether you can add a configuration option where a user defined allowed overshoot can be specified before the Diyless goes into idle mode? Default can by 0 which is the current implementaton when the room setpoint is exactly matched. However it would help my heatpump tremedously if I can specify an allowed overshoot of a value between 0,1 to 0,6 degrees above room setpoint. Still, when my heatpump runs at its lowest heat power performance but the temperature does not drop, the heatpump still needs to be stopped by the Diyless when the allowed overshoot is consumed.

This feature allows my heatpump can handle the overshoot by lowering its heat output and thus matching the requested room setpoint without frequent stops / starts. And it also still safeguards a hard stop when the overshoot becomes to high due to warm wether conditions.

Thanks in advance for your response. Kind regards, Edwin Noordeloos

[diyless]

Dear @Edwin184 , Thank you very much for your detailed description. In the next version, we plan to add additional configuration options for the heating algorithm. Perhaps they will be useful for your case.

Best regards, DIYLESS

[Edwin184]

@diyless As the new heating season is starting, any update on the next version? I don't want to put any pressure as I'm very happy with the current release of the thermostat, it is really working great. So if no new release comes I'm still happy.

But as I always am looking for optimization, a little more headroom on the overshoot of 0,1 or 0,2 degrees would help improve the COP of my heat pump and lowers the number of start/stops. And of course the downside is it also increases the room temperature hysteresis. So it would be great if it would be user defined so I can find the optimal value for me.

Kind regards, Edwin Noordeloos.

[Edwin184]

@diyless , gentle reminder, any update on the next version? Currently the hysteresis is fixed on thermostat off = room temperature + 0,07⁰C and thermostat on = room temperature - 0,00⁰C. Some more configuration flexibility on hysteresis would help my heat pump a lot on limiting the number of start/stops as it needs about +0,2 to +0,3 to stabilise (to lower heat output).