Problems with hot water using Vitocal 200-S

Good day,

I have problems with the hot water preparation with my Vitocal 200-S heat pump. The hot water reaches a temperature of 43 degrees, although a hot water temperature of 50 degrees should be possible with a flow temperature of 55 degrees. What could be the reason for this?

I have observed that as soon as the flow temperature has reached 55 degrees, the heat pump switches off quite quickly.

Thank you very much

I just spoke with the craft business. I was told that you had spoken with Viessmann and Viessmann said that without the electric heating element you can reach a maximum of 43 degrees and that I should turn on the electric heating element. But that is not normal, is it? You should be able to reach about 50 degrees of hot water with a flow temperature of 55 degrees, right?

Hello,

....I have observed that as soon as the flow temperature reaches 55 degrees, the heat pump switches off quite quickly.

This manufacturer does not publish complete COP and performance curves for the usual flow temperature heating (35°C) and domestic hot water (50 or 55°C). A knave who suspects evil here.
According to the datasheet, flow temperatures up to 55 °C are achieved. However, it is not revealed whether this is only possible with the help of the heating element.
The tabular triple-point data (heating operation) are also completely insufficient for an overall assessment.

...But that is not normal, is it?

Unfortunately, it is here. Depending on the proportion of domestic hot water production in the total energy demand, a rather modest overall annual performance factor will probably result here. Not necessarily desirable.
Who planned this system?

Best regards.

Hello,
I spoke with the technical service of Viessmann today. I was told that at least 48 degrees (possibly even more) are definitely achievable.
I was told to read the temperature sensors after the heat pump switches off. I did that.
I read the following values when the heat pump switched off.
Outside temperature: 30 degrees
Flow temperature. secondary: 55 degrees
Return temperature. secondary: 52 degrees
Storage temperature. top: 42 degrees