I depends on which indoor unit you have,
I think that the Thermia ITEC is the product name for outdoor unit to which you can connect several different inddor units. Some of these are compatible with ThermIQ, some are not.
If compatible you will be able to run the heatpump in “heastpump only” or “electric heater only” mode (as well as auto). You can not directly turn on or off the electric heater.
The indoor Unit will be the thermia itec 8 plus (im Not sure with the name, maybe just “thermia plus“). Is thermiq connected to the indoor Unit or the indoor and the Outdoor Unit with a cascaded Bus ?
Thank you 🙂