I thought it might be useful for the Vaillant Arotherm heatpump and its owners to have their own thread. So any questions, queries, things we’ve learnt and performance chatter can go in here. For starters, anyone looking for in depth performance information, this technical document from the Czech …

What I have done is use Home Assistant to adjust the Heat Curve based on the difference between the actual temperature and the target temperature. The setting I use is to set a curve of 0.8 if the actual is 0.5°C or more below target. I decrease the Heat Curve by 0.05 for each 0.1°C increase of the …

Thanks for the comment, that’s a good idea. Are you able to DM me a screenshot of how you did that? I wanted to avoid using 3rd party tools to manage things, and keep it as simple as possible, but shoulder seasons and lack of sun see to be our trouble point.

[image] iccaldwell: What I have done is use Home Assistant to adjust the Heat Curve based on the difference between the actual temperature and the target temperature. I thought that you could only read data and not write / change anything. How did you manage to make changes from Home Assista…

If you look at the devices of the MyVaillant integration, anything that shows as a control is just that - you can control it. You can change them manually or set up automations.

I have set up an automation: - id: "set_heat_curve" alias: "set Heat Curve" mode: queued trigger: - trigger: state entity_id: number.dynamic_heat_curve action: - service: number.set_value target: entity_id: number.heat_pump_circuit_0_heating_curve data: …

[image] Matching primary/secondary flow Heatpump Hi everyone, I’m trying to match the primary and secondary flows in my system and would appreciate some advice. Vaillant aroTHERM plus VWL 105/8.1 A and a 45 L buffer tank used purely as hydraulic separation. H…

I would increase secondary flow rate as far as you can but keep it below primary so the hot water from the heat pump is pushed down the tank (assuming flow is at the top and return at the bottom). Faster secondary will reduce dt across the rads which will reduce the effect of mixing and pushing wa…

Thanks jamespa! The problem is that the radiators become loud when I increase the secondary flow and I’m not sure if the pipes can handle it. When throttled to 40% the heat pump flow is reduced to ~1100 L/h and the deltaT increases. The question if there are any downsides of not having the pump on A…

Despite the fact that I have a Vaillant I haven’t yet worked out what auto pump mode does exactly, it still seems to run at fixed speed. The fundamentals are the same as ever though, the lower the flow temperature you can run at the more efficient all else being equal. If deltaT increases you have…

[image] jamespa: it still seems to run at fixed speed. In Auto mode speed is determined by max.rem.head. the lower this is set, the lower the flowrate. For minimal flow resistance like into a 4-port buffer, even the lowest settings might give high flow.

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kookoo (HK) 15 March 2026 00:32 1170