What TPI control types are available on the RT520 thermostat?

The RT520 offers 3 types of TPI (Time Proportional & Integral) control: 1. for radiator heating (6CPH), 2. for underfloor heating (3CPH), and 3. for electric heating (9CPH). TPI is a self-learning algorithm that ensures economical system operation and minimizes energy consumption. Note that choosing TPI excludes the SPAN option, and vice versa.