What is OpenTherm (OT)

Open Therm (OT)   

is a standard communications protocol used in central heating systems for the communication between a central heating boiler and a thermostatic controller.

As a standard, open therm is independent of any single manufacturer. A controller from manufacturer A can in principle be used to control a boiler from manufacturer B. However, OpenTherm controllers and boilers do not in fact always work properly together. The openTherm standard comprises a number of optional features and some devices may include manufacturer-specific features. The presence or absence of such features may impair compatibility with other OpenTherm devices.