Description

An electric three-way valve serves as a multifunctional intelligent control valve for modern HVAC systems. It supports multi-flow control and seamlessly switches between different mediums, like heating and cooling, ensuring precise fluid regulation.

Types of Electric Three-Way Valves

1. The three-way mixing valve combines two fluids into one through the valve.
2. The three-way diverting valve splits one fluid into two streams through the valve.

Function

The electric three-way valve controls hot or cold water flow into the fan coil unit. Unlike the two-way valve, it allows excess water to bypass back into the system, maintaining a near-constant flow rate. It can also stop water flow to the coil and redirect it to the return pipe, solving issues from flow stoppage when a two-way valve is closed. This function allows complete water shutoff, saving energy and preventing coil condensation.

Installation

To reduce costs and improve performance, units below 10 kW usually require one three-way valve, while units above 10 kW need two or more. Install the three-way valve in the terminal of the most frequently used room, such as the living room, where cooling demand is highest. Installing it in an unused area can reduce cooling capacity in frequently used rooms.

Design the system with a service factor to choose a slightly smaller main unit. This method may restrict three-way valves to some terminals, reducing water flow and cooling capacity. If all terminals shut off, water flow through the three-way valves may not meet heat exchange requirements, causing a large temperature difference between inlet and outlet water, potentially triggering a low water temperature alarm (not a water flow alarm).

Use electric two-way valves for fan coil units and three-way valves for remote units. This setup eliminates the need for a differential pressure bypass valve, allowing the terminal to bypass in the water system. Installing both valve types on the return pipe of fan coil units prevents water flow interruption when all two-way valves are closed.