Vitotrol 200E without outdoor temp. sensor

[RobyM]

Good morning everyone,

I would appreciate your advice.

I have just had a Vitodens 222W B2LH-19kW boiler and a Vitotrol 200E controller (connected via PlusBus) installed. Unfortunately, it is not possible to install the outdoor temperature sensor because there is no way to run a cable to the north-facing side of the house. The technician claims that the Vitotrol 200E only works if an outdoor sensor is connected; therefore, instead of the sensor, he installed a fixed resistor to simulate an outdoor temperature of 10°C. In my view, this is not ideal, as adjusting the flow temperature now requires manually tweaking the heating curve offset and referencing the value corresponding to 10°C. I would prefer to use a control mode based on the indoor ambient temperature. Is this mode possible with the Vitotrol 200E, and what happens if no outdoor sensor is connected?

Thank you for your advice.

Roby

[divanc]

Hallo @RobyM 

das funktioniert, sofern das Vitotrol tatsächlich im Referenzraum installiert ist.
Sie müssen die Parameter für den witterungsgeführten Betrieb mit Raumtemperatureinfluss (933.6) sowie den Faktor für den Raumtemperatureinfluss (933.7) konfigurieren.

Ohne Außentemperatursensor funktioniert dies jedoch nicht; sollte die Installation eines solchen Sensors nicht möglich sein, muss stattdessen ein Widerstand eingesetzt werden.

Dies haben Sie bereits berücksichtigt.

VG

[RobyM]

Good morning, thank you for your response. I have a single Vitotrol 200E unit. I would appreciate some clarification, if possible:

According to the manual, there are three operating modes:

1. Weather-compensated

(with or without room temperature influence)

2. Room temperature-dependent operation

3. Constant temperature operation

I would like to know whether it is possible to use the Vitotrol in mode 2—that is, without weather compensation. In effect, would the Vitotrol function like a simple room thermostat, allowing me to easily set the flow temperature myself? Or is it mandatory to use mode 1?

Thank you.

[divanc]

Hello @RobyM 

For Mode 2, a room thermostat—not a Vitotrol—is required.

It only functions in Mode 1 if the Vitotrol is actually installed in the reference room.
You need to configure the parameters for weather-compensated operation with room temperature influence (933.6) and the room temperature influence factor (933.7).

It will not work without an outdoor sensor; therefore, if installing a sensor is not possible, a resistor is strictly required.
You have already taken care of this.

The service instructions are attached.

 Best regards

[RobyM]

Okay, thank you very much for the clarification. Hopefully, in the future, Viessmann might offer an external wireless weather sensor, or at least allow the outdoor temperature to be determined via an internet-based weather service.

Have a great day.