Two-way and three-way valves in fan coils: operation and differences

Valves control the water flow to the fan coil and directly affect both the thermal efficiency and the hydraulic behavior of the system.

Two-way valve

Varies or shuts off the flow through the fan coil. It is very frequently used in variable flow systems.

Three-way valve

Can divert or mix the flow to maintain a more constant overall flow rate in the circuit.

Relationship with the circulator

Two-way valves require proper differential pressure control when multiple zones open and close.

Proper application

The choice depends on the network design and should not be changed without a comprehensive evaluation of the hydraulic system.