Floating control is a two-position or three-position control strategy where a valve or damper continuously moves (floats) toward fully open or fully closed positions based on error between setpoint and actual temperature. Unlike proportional controls that modulate smoothly, floating controls use neutral zones and directional movements to regulate system output. This simple on-off approach reduces energy consumption in less critical applications.
Technical Details
Three-position floating control divides operation into cooling, neutral, and heating modes with 1-3°F deadbands separating each zone. The controller outputs ‘increase,’ ‘decrease,’ or ‘stop’ commands that drive the valve continuously until the setpoint is satisfied. Most systems complete full valve travel in 120-180 seconds, creating slower response compared to proportional strategies.
Applications
Floating control works well for non-critical space conditioning in perimeter zones where slow temperature swings are acceptable. It simplifies control of three-way mixing valves in low-mass hydronic systems and moderates supply temperatures in fan coil applications.
Practical Significance
Floating control reduces component wear by eliminating constant modulation, extending valve and actuator lifespan by 20-30 percent. It requires less sophisticated control electronics and calibration, reducing installation complexity and maintenance costs for smaller buildings.