Viessmann vitotronic 200 kw2 + Vitola 100

Antoniu

Hello,

Please advise on equipment.

Viessmann vitotronic 200 kw2 + Vitola 100 (old, but serviced and everything works).

Problem:
I set the DHW temperature to +39C. I set the temperatures on and off: +/- 1K, i.e. I expect the Cylinder primary pump pump to work from + 38C to + 40C. But I see on the screen that the pump works at +41C and +42C. At this water temperature, the burner turns on unnecessarily at + 47-48C of DHW water, apparently only because of the hot water supply, and this is an excessive consumption.

Settings:
code А2:0 (Without cylinder priority control applicable to heating circuit pump and mixer. Both heating and water heating work)
code 59:1 (+/- 1K)
Code 60 (boiler water temperature during hot water heating) +10K.
Code 61:1 (The cylinder primary pump starts immediately)
Code 62:0 (Cylinder primary pump without run-on)

I control the temperature of hot water through (i).
The burner turns off somewhere at + 51-52C. By inertia, it reaches + 53-54С.

Tried both modes - the same:
1) Top and bottom borders (default +/- 2.5K, I changed to +/- 1K)
2) Adaptive cylinder heating

The pump runs intermittently, still sometimes turns off.

Why did I get there.
Initially, the priority of the DHW was turned on - for the time of heating the water, the heating pump was turned off, and it became cold in the house, because it dragged on for a long time. Initially, the boiler water was set to + 20K. The burner heated the boiler up to + 67-71C.
When setting +39C hot water, the Cylinder primary pump still worked even at +42-43C.

The rest of the equipment works fine, there are no complaints about water.

Tell me - why does not the Cylinder primary pump turn off?

Paul Pollets

If the water tank reaches 50C., it's working. It may overshoot by 3-5 degrees. If it fails to hold or reach setpoint, the board may be glitching

Alan (California Radiant) Forbes

Could be a bad DHW sensor. It could also be that there's a mineral buildup in the indirect (cylinder).

Normal DHW temperature is 52°C (125°F). Is 40°C (104°F) better for you?

Where do you live?

Antoniu

Hi guys,

I have found the reason:
code 59:1 is only for the pump turn on in Vitotronic 200.
So with 39°C: pump turns on 38°C and turns off on 42°C.

DWH 39°C-40°C is a recommendation of the previous owner.

My indirect heating boiler is around 400 liters.
Using +20K ( +57-64C) the speed of heating is 2°C per hour.
It takes too much time: 2 hours from +39 to +42C.

It is time to clean the indirect heating boiler?
The power is too low.

Paul Pollets

the tank rarely needs cleaning, unless you have hard water. It should be set for 50 deg C. The boiler needs cleaning and service at least every 12-14 months