Why do control valves go on the return?

Why do control valves go on the return?

With a control valve on the return side, the water is at a higher pressure through the coil, reducing offgas, thereby lowering dissolved oxygen content.

What is 2 way valve and 3 way valve in HVAC?

A 2-way valve is any type of valve with two ports: an inlet and an outlet port, typically labeled “A” and “AB” respectively. 3-way valves are commonly found in constant flow/volume pumping systems and can be either mixing or diverting valves. 3-way valves can be piped in the supply or return.

What are the valves used in chilled water system?

Water Chiller, the heart of HVAC system, has valves on inlet and outlet lines of chilled water and cooling water. These valves are usually gate and globe valves which are used for isolation and throttling purposes.

Does a control valve go on the supply or return?

Water coil 2-way control valves motorized with an electric actuator can be installed in the supply pipe but the standard installation practice is to install the valve in the return pipe because the media water temperature is tempered. …

How does a balancing valve work?

Dynamic balancing valves work as flow limiters. They are set to a desired flow rate and ensure that a larger flow rate does not take place. If the pressure in front of the valve increases, it will close some more, so the pressure loss across the valve becomes correspondingly higher.

What is a 3 2 way valve?

A 3/2-way valve has three ports and two positions that can be driven pneumatically, mechanically, manually or electrically via a solenoid valve. They are used, for example, to control a single-action cylinder, driving pneumatic actuators, blow-off, pressure release and vacuum applications.

How does a 3 way valve work?

A 3-way ball valve works by turning the handle, which rotates a ball in the valve body, to align the cut-out channels in the ball with the inlets and outlets of the valve. The “L” shape cut-out of the ball on an L-port valve sends fluid through 90 degrees from one port to another.

How does a 3 way 2 position valve work?

Three-way, 2-position valves typically feature a three-ported design allowing flow paths in several different configurations, while only connecting two ports in any single position. The “normally open” design allows flow to travel from the pressure port when at rest; the “normally closed” design does not.

What does a 2 way control valve do?

A 2-way valve can be used to control heating and/or regulate the flow and temperature. 2-way valves feature two ports — an inlet and an outlet port.

Where do balancing valves go?

Shifting viewpoints on flow controls can cause disagreements where balancing valves should be located in closed loop systems. Many (including us at Hays Fluid Controls) agree that the balancing valves should be placed on the return side, whereas other companies may choose the supply side.

What is the function of 2 way valve?

2 way valves are commonly found in basic on/off applications, where they are frequently referred to as isolation valves. These valves are an essential component in many process safety systems, as they can immediately stop fluid flow to a specific location in the event of an emergency.

When to use 2-way or 3-way valves in chilled water line?

In Chilled water line Criteria to use2 or3-way valve depends on the application type: 1. flow and secondary Variable speed pump. 3-way valves are not suitable for this system. 2. 2-way valves are recommended in Primary only Variable speed pump.

What is the difference between 2 way and 3 way valves?

2-Way and 3-Way Valves. 2-way valves are pretty simple and straight-forward. A 2-way valve is any type of valve with two ports: an inlet and an outlet port, typically labeled “A” and “AB” respectively. 2-way valves are used in many applications, from basic on/off to more complex variable flow applications with pumps and VFDs.

What is the return water temperature of a 3 way valve?

The return water temperature is 160°F when half of the flow is through the coil and half is in bypass. The use of three-way valves normally means the flow rate is constant and the return temperature varies.

What is a 2 way valve on a water heater?

A 2 – way valve is a straightforward device with two openings, one for inlet and the other for outlet. The se chilled water control valves simply regulate the flow of the fluid through them by varying the size of the valve opening, and can work as on/off devices.