How Does a 3 Way Ball Valve Work

A 3-way ball valve looks simple from the outside, but internally it is doing more than just on or off. With three ports and a ball that has an L or T-shaped bore, a 3-way valve can divert, mix, or split flow in a compact package. Understanding how the ball moves and which ports connect in each position is critical before you drop one into a piping diagram.

This guide walks through the basics of how a 3-way ball valve works, how L port and T port patterns behave, and where 3-way electric ball valves make sense in real systems.

What is a 3 Way Ball Valve

A 3 way ball valve is a quarter-turn valve with three ports instead of the usual two. Inside the body is a drilled ball that rotates 90 degrees to connect different combinations of ports.

At a high level:

• Ports: Three threaded or flanged openings, often labeled A, B, and C.
• Ball: A spherical ball with an L or T-shaped hole.
• Seats: PTFE or similar seats support the ball and provide a shutoff. 
• Stem and seals: Connect the ball to the handle or actuator and keep media inside the valve.
• Actuator or handle: Manual lever or electric actuator that rotates the ball a quarter turn.
  
  

Media flows through the hole in the ball. When you rotate the ball, you change which ports are linked together.

L Port vs T Port 3 Way Ball Valves

The key to understanding a 3-way valve is the shape of the bore inside the ball.

• L port (diverting): The ball has a capital “L” cutout. It connects the center port to one side port, then the other, typically at 90-degree rotations.
  
  
• T port (mixing or splitting): The ball has a capital “T” bore. It can connect all three ports together or connect the center port to either side.
  
  

L port vs T port summary

Feature	L Port 3 Way Ball Valve	T Port 3 Way Ball Valve
Bore shape	L shaped	T shaped
Typical function	Divert flow between two outlets	Mix two inlets or split one inlet to two outlets
Common connection pattern	One common port, two alternates	One common port, two additional ports, all can connect
Can connect all 3 at once	No	Yes, in many positions
Typical use	Send flow to Tank 1 or Tank 2, or Line A or B	Blend hot and cold, split a feed to two branches

Many 3-way electric ball valves in the Electricicsolenoidvalves catalog use an L port pattern for reliable diverting between two flow paths.

How the Flow Paths Change When You Turn the Valve

To keep things simple, assume the center port is the “common” port.

L port operation, step by step

Imagine the ball as a capital L that always includes the center port.

• Position 1, 0 degrees
  
  
• Center port connected to Port A
  
  
• Port B blocked
  
  
• Position 2, 90 degrees
  
  
• Center port connected to Port B
  
  
• Port A blocked
  
  

Some L port valves also have an intermediate position where the leg of the L overlaps both side ports, but that depends on the internal design and the travel range offered by the actuator.

In practice, an L-port 3-way ball valve is usually used as a diverter:

• One pump or supply line feeding two different destinations.
  
  
• One tank feeds two downstream processes.
  
  

T port operation, step by step

For a T port, picture a capital T with the stem often aligned with the center port.

Depending on the manufacturer and seat drilling, a T port valve can be set up so that:

• Position 1
  
  
• All three ports are connected.
  
  
• Position 2
  
  
• Center port connected to Port A only, Port B blocked.
  
  
• Position 3
  
  
• Center port connected to Port B only, Port A blocked.
  
  

By mixing hot and cold feeds into a common outlet, or by splitting one inlet into two outlets, T port designs can do mixing and distribution in one valve body.

Because there are multiple possible drilling and stop arrangements, you should always confirm the manufacturer’s flow diagram before committing a T port valve to a control scheme.

Main Components of a 3 Way Electric Ball Valve

A 3-way electric ball valve swaps the manual lever for an electric actuator on top of the ball. The internals are similar; the control is automated.

Typical construction for Electricsolenoidvalves 3-way electric ball valves:

• Body: Brass, with NPT threaded ports for easy integration into water, air, and many chemical lines.
  
  
• Ball: 316 stainless steel for corrosion resistance.
  
  
• Ball seat: PTFE to provide low friction and tight shutoff.
  
  
• Seals: Viton for broad chemical compatibility within the listed pressure and temperature limits.
  
  
• Actuator: XR33 3-wire actuator on many models, 9 to 24 V AC or DC supply, internal control electronics, IP67 enclosure rating to handle splashing and outdoor environments.
  
  
• Port sizes: Commonly 1/2, 3/4, and 1 inch NPT in the current lineup.

The actuator rotates the ball approximately 90 degrees, which switches the flow from one port combination to another. On typical Electricsolenoidvalves.com brass 3-way electric ball valves, full position change takes around 5 seconds, which helps reduce water hammer compared to snap-acting valves. 

Manual vs Electric 3 Way Ball Valves

You will see both manual and electric 3-way ball valves in real systems. Functionally, the flow paths are the same; the difference is how you move the ball.

Manual 3-way ball valves

• Hand lever attached directly to the stem.
  
  
• Good where an operator is physically present.
  
  
• Simple, no power required.
  
  
• Best for infrequent repositioning.
  
  

Electric 3-way ball valves

• Motorized actuator that turns the ball automatically.
• Controlled by PLCs, thermostats, level controllers, or simple switch logic.
• Better choice when:
  
  
• You need a remote control.
  
  
• You are tying into automation.
  
  
• The valve is in a hard-to-reach area.
  
  
• You need predictable timing and repeatability.
  
  

Electric 3-way ball valves on Electricsolenoidvalves.com use a 3-wire control on many sizes. One lead is common, one opens toward Port A, one opens toward Port B, and the actuator holds its last position when power is removed. 

Common Ways 3 Way Ball Valves Are Used

A 3-way valve solves problems that would otherwise need multiple 2-way valves.

Examples:

• Diverting a single source to two destinations
  
  
• One pump feeds either Tank A or Tank B.
  
  
• One cleaning solution line feeds two wash stations.
  
  
• Mixing two feeds into one outlet
  
  
• Hot and cold water mixing for process temperature control.
  
  
• Two chemical concentrates are blended before a downstream reactor.
• Selecting between two sources
  
  
• Switching between two supply tanks without breaking the line.
  
  
• Switching between city water and a booster pump line.
  
  
• Maintenance and bypass
  
  
• Routing flow around an offline filter or heat exchanger by turning one valve instead of manipulating several.
  
  

For more application depth, you can send the reader to Electricsolenoidvalves  existing article on the industrial use cases for 3 way electric ball valves. 

How to Choose the Right 3 Way Ball Valve

You do not pick a 3-way valve just by size. The port pattern and seat drilling matter as much as the body size.

1. Flow function

• Do you need to divert a single stream between two branches?
  
  
• Start with an L port pattern.
  
  
• Do you need to mix two feeds or split one feed, while sometimes connecting all three ports
  
  
• Look at T port patterns and confirm the manufacturer’s flow diagram. 

2. Port labeling and diagrams

Always verify:

• Which port does the manufacturer label as common?
  
  
• Which ports are connected in each actuator position?
  
  
• Whether an intermediate position is allowed or if the actuator uses two hard stop positions only.
  
  

Electricsolenoidvalves’ 3 way electric ball valve product pages include flow diagrams showing the L port pattern and which ports link in each energized state. 

3. Size, pressure, and temperature

• Match the line size to the threaded port, often 1/2, 3/4, or 1 inch NPT on current brass 3-way electric ball valves.
  
  
• Confirm the pressure range, for example, up to 185 psi on some Electricsolenoidvalves models with no minimum pressure.
  
  
• Confirm the temperature range, for example, roughly 15 to 250 °F on many brass 3-way ball valves with PTFE seats and Viton seals.
  
  

4. Materials and media

Select materials based on the fluid:

• Body: Brass for water, air, many oils and glycol blends, stainless for more aggressive media.
  
  
• Seat: PTFE is common and covers many applications within the pressure and temperature ratings.
  
  
• Seal: Viton for many fuels and chemicals; check compatibility charts if you are near the edge of the envelope.
  
  

If you are uncertain about body and seal compatibility, Electricsolenoidvalves recommends checking a chemical compatibility resource or contacting support before final selection. 

5. Electrical and enclosure details

For electric models:

• Voltage, for example, 9 to 24 V AC or DC on XR33 actuators.
  
  
• Wiring style, 3-wire control vs other modes.
  
  
• Enclosure rating, such as IP67 or NEMA 4 equivalent, for outdoor or washdown environments. 

Browse our 3-way electric ball valves to see brass, full port options with PTFE seats, Viton seals, and IP67-rated actuators. If you are not sure whether you need an L port or a T port, send us your line size, media, and a quick sketch of your flow paths, and our team will recommend the right valve for your setup

Quick FAQ: Is a 3 way ball valve the same as a 3 way solenoid valve

No. A 3 way ball valve uses a rotating ball and seats, while a 3 way solenoid valve uses a poppet or spool operated by an electromagnet. Both can divert or mix, but ball valves are better suited to larger line sizes, full port flow, and higher shutoff integrity in many piping systems. Solenoid valves shine in smaller bore and fast acting duty. 

Q: Can a 3 way ball valve fully shut off flow

Many L port and T port designs have a position that isolates one or more ports, but it depends on the drilling pattern and stop arrangement. Always check the manufacturer’s flow diagram if you need a hard shutoff position across specific ports.

Q: Do I always have to use the center port as the common port

No, but it is common practice and aligns with many flow diagrams and actuator markings. Some manufacturers allow alternative port assignments. If you intend to use a side port as the common port, verify that the internal ball drilling and stop positions support your required flow pattern. 

Q: When should I choose an electric 3 way ball valve instead of manual

Use an electric 3 way valve when you need remote operation, automation, frequent cycling, or the valve is hard to reach. Manual 3 way ball valves are fine for low cycle, attended systems where an operator can physically move the handle.