Floor sensors are required where the floor cannot exceed a maximum temperature, or needs to maintain a specific temperature. Where temperatures cannot exceed a maximum temperature, (usually adhesive or wood floor finishes) the floor sensor is set to a maximum limit which will cut out when this temperature is reached. The thermostat will re-engage once the temperature reduces by 1-2°C.
For example, a poorly installed system with pipes spaced too close together, or a sensor directly above a pipe will continually be turning on and off as the floor sensor heats too quickly, therefore taking a long time to achieve room temperature.