How do temperature fluctuations occur in fresh water?

No, because that is not the purpose of the forum. You can gladly post that here.

ok. But can one say that the buffer temperatures are appropriate? 65 degrees flow to produce 58 degrees at 53 degrees circulation. Or too high? Or too low?

Absolutely sufficient for good fresh water. Whether it is too much, we cannot know, as we do not know the maximum simultaneous demand of your residents. Only you know that (or can determine it).

You can only approximate the minimum setting empirically. The thermometer helps with this, or possibly the system control if you can read real-time temperatures there.

With good fresh water absolutely sufficient. Whether it is too much, we cannot know, since we do not know the maximum simultaneous demand of your residents. Only you know that (or can determine it).

You can only approximate the minimum setting empirically. The thermometer helps with this or possibly the control of the system if you can read real-time temperatures there.

Good day.
Could you maybe give me advice once again?
Is it possible that if too little hot water (e.g. when showering) is used, temperature fluctuations can occur (cold spurts again and again in between)?
The buffer is fully loaded (at about 70 degrees), the fresh water runs at just under 60 degrees, but only very little hot water is used during showering.
I have also noticed this. When showering "hotter," these fluctuations do not occur. Only when the single-lever mixer is set to just slightly warm.
It cannot be lack of power. Rather, that too high temperatures are coming from the forward flow.

I can try , but my crystal ball doesn’t reveal much.

Overall, it sounds either like too little heat in the buffer supply or a control problem with the fresh water charging pump.

Too little heat: If your read tennis station temperatures are correct, there should be a thermal short circuit causing too cool water to enter the fresh water. We can investigate this if we have an exact hydraulic diagram including the internal structure of the buffer tank. How is the buffer charged, exclusively via the wood gasifier? What kind of return flow lift does it have installed?

Control problem of the charging pump: I could imagine this more. When little hot water is tapped, it starts to charge the fresh water. Due to the very decent buffer temperature, the fresh water heats up well (above maximum temperature) and the charging pump switches off instead of continuing to charge with low volume flow and producing a constant temperature at the fresh water outlet. So basically an override overshoot of the control. Causes can be varied: too high minimum volume flow on the tapping side, defective sensors, defective charging pump, etc... You can find this out if you at least observe all temperatures and the pump speed or the pump volume flow during a shower process. Do you have a chance for that?

I can try , but my crystal ball doesn't reveal much. That sounds overall either like too little heat in the buffer supply or a control problem with the fresh water loading pump. Too little heat: If your read tennis stattion temperatures are correct, there should be a thermal shortcut causing too cold water to be supplied to the fresh water. We can investigate that if we have an exact hydraulic scheme including the internal construction of the buffer tank. How is the buffer loaded, exclusively via the wood gasifier? What kind of return flow lift is installed? Control problem with the loading pump: I could imagine this more likely. When little warm water is tapped, it starts to load the fresh water. Due to the quite decent buffer temperature, the fresh water heats up a lot (over maximum temperature), and the loading pump switches off instead of continuing to load with low flow and generating a constant temperature at the fresh water outlet. So basically an overshoot of the control. Causes can be manifold: too high minimum flow rate on the tapping side, defective sensors, defective loading pump, etc. You will find out if you can observe all temperatures and the pump speed or the pump flow rate during a shower process. Do you have that possibility?

Hello. Thanks for your info. I will check the values during a shower. But: Could it possibly also be due to this? Buffer temperature high 70 degrees. Supply to fresh water mixed to 65 degrees by a domestic hot water mixer. 65 degrees to fresh water, to produce 58 degrees. If very little lukewarm water is drawn for a short time, it could be because the domestic hot water mixer (which is a thermostatic mixer) is too slow, and thus the colder buffer water affects the supply temperature to the fresh water for a short time. However, if you run the lukewarm shower water longer (without constant interruption), the temperature should be kept steadily lukewarm. I have to test that. Or could the problem be that with little low hot water short cold phases appear? Thanks

Hello. Thank you for your information. I will check the values during a shower. But: Could it possibly also be due to this? Buffer temperature high 70 degrees. Supply to the fresh water mixed to 65 degrees through a domestic water mixer. 65 degrees to the fresh water to produce 58 degrees. If now very little lukewarm water is drawn for a short time, it could be because the domestic water mixer (which is a thermostatic mixer) is too slow, and therefore the colder buffer water briefly affects the supply temperature to the fresh water. However, if you run the lukewarm shower water for longer (without constant interruption), the temperature should be kept stably lukewarm. I have to test that. Or could the problem be that at low warm water consumption these cold phases come briefly? Thank you

PS: If I possibly reduce the buffer temperature from 70 degrees to 66 degrees, then that should be enough supply for 58 degrees at the fresh water. Then almost nothing should be mixed at the mixer. Even with low consumption, right?!?