Buderus Dual-Function Stove: Inconsistent Water Temperature - Hot & Cold Shower Solutions

Hello, I have a Buderus dual-function stove in my house, and while there are no problems with heating to radiators, when it comes to heating water, it's a tragedy. You can't practically take a shower, because the water runs once hot that it burns, and then it's lukewarm almost cool and then hot again. What is the reason for this?

thanks for advice

greetings

I understand that it is a stove without a boiler, it turns on when you open the tap. A better solution is an exchanger. In this case, if you do not want to make a revolution in the boiler room, buy a thermostatic faucet for the shower.
Also, call a professional installer to adjust the furnace if necessary. It happens that you have different temperatures because when you open the tap, winter is flying in the pipes, then it is heated and hot. If you release a weak stream, the stove may not sense the flow of water and will not turn on / turn off - it starts to fly cold then .....
furnace for regulation and mercedes among the batteries

Regards

at my mother-in-law's, but not in the house, but in an apartment in a tenement house, there is also a dual-function stove, and when she turns on the water, it is cold at first, but when it comes down from the pipes, then the temperature is the same as on the stove all the time, e.g. 40 degrees, and for me set to 50, and sometimes it flies so hot that you can't keep your hand under the water. Only the content section from the stove to the taps is 1m, and mine is about 5m. Well, I don't know why, but I have low pressure on hot water, it's ok on cold water, and when I turn on hot water, there is no such strong pressure. it turns on and off again. Is it supposed to be like this?

that is, you have a problem with the pressure, you can't receive hot water and the stove goes out, then lights up again when it drains. Check out this silence.

Gentlemen, I have a similar problem this time in a double-function furnace with a closed combustion chamber Neckar, this is exactly the same as Junkers. In each battery and in the kitchen (2 m from the stove) and in the bathroom (3 m from the stove) and in the shower (1 m from the stove) hot and cold water flows once (the stove turns on and off every now and then). There was a specialist from the service who charged me almost PLN 200 and it seemed to me that for some time it was fine, but nothing is still the same now. Did maintenance and cleaning. It's been 2-3 months now. It is very annoying in the shower. I'm afraid that someone else will come and spend money and it will be the same. So I want to be interested in the subject myself. I suspect some thermostat that when the temp reaches a certain temp it is broken and instead of holding it, it strikes. Has anyone ever had this problem? I would like to add that the stove has been running for 7 years, there have never been any problems and now it appeared basically with the beginning of the heating season in October.

@GabiiWojtek
Damaged hot water sensor or calcified plate heat exchanger.

I want to start with descaling, is this about adding Sentinel X400 to the CO system?

A good choice.

It's a waste of money for this Sentinel X400. I checked it and it costs PLN 180 and I decalcified for a few PLN. I just unscrewed the exchanger (two small screws screwed from the bottom. Only when draining the water, due to the small amount of space near the stove, it was hard to reach and stretch a bit.
And I decalcified by pouring citric acid with boiling water several times, I used 4 acids in total, but it was super clean, you can see that it's clean inside. It was at the beginning because the cheapest one. Now I am waiting for the replacement of the ntc sensor, it is even simpler but a little more expensive because for a new one you have to pay at least PLN 60 + transport. But I feel that mine is good, maybe something will tell you the resistance at room temperature after dialing 12.6 kohm, after putting it in hot water it dropped to about 3 kohm and after pulling it increased to 4,5,6, .. etc. That's why I think he's ok but maybe is that not relevant?
If it's ok, it means that it's a disc, I think something will jump on it because when I was processing my washing machine, after reanimation by professionals, it turned out that these washing machines are programmed for a number of cycles and something burns out. So I think it will end there, what is the cost of replacing the electronics (main board) of this tz n Neckar NW 21-1 AE (i.e. Junkers) furnace and is it worth it in a 6-year-old furnace?