Technical Service Bulletin

ViCare registration results in E10 / E12 error

Applies to: Multiple series of Vitodens 100/200 (details below)

Important Disclaimer

The information in this bulletin is intended exclusively for licensed heating contractors, and is NOT intended for the end user. This material is NOT intended to take the place of the information contained in the manuals shipped with the product.

Use of this information by unqualified personnel may result in property damage, personal injury or death.

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Applies to:

◾   Vitodens 100-W, B1HE / B1KE Series (all models)
◾   Vitodens 200-W, B2HE Series (all models)



E10 or E12 error occurs when a user tries to register their boiler with the ViCare app.



A number of Telemetry Control Units (TCUs) which are used in Vitodens 100 and  Vitodens 200 series boilers were manufactured with firmware that contains an invalid certificate.

When the registration process takes place, ViCare passes Wi-Fi credentials to the TCU and instructs it to connect to the Viessmann cloud (the back-end service). ViCare then also connects to the Viessmann cloud and waits for the TCU to check in.

Because the TCU has a bad certificate, the connection to the cloud server is rejected. Instead, it's directed to a "recovery server" or "zero-series update server" which tells the TCU to update it's firmware. This update process can take anywhere from 60 to 90 minutes.

Once updated, the TCU can connect to the back-end server. However, the registration process has already been interrupted by a time-out, and this results in an E10 or E12 error.



After the user receives error  E10 or E12 in ViCare, they will need to wait a minimum of 90 minutes while the firmware on the TCU gets updated.

After this time,  the user can try registering the boiler in ViCare again, and the process should work now that the firmware has been updated.


Viessmann Technical Services


Bulletin ID:


Date issued:

January 25, 2024

Updated on:

January 25, 2024

Revision #:


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