3-Way and 4-Way Ball Valves: L-Port, T-Port and X-Port Explained
When you need to send flow one way or another, split it, combine it, or reverse it, the port pattern of a multi-port ball valve decides what is actually possible. Two valves with the same body and the same number of ports can behave completely differently depending on how the ball is drilled. This guide explains the common patterns so you can specify the one that does the job.
What is the difference between L-port, T-port and X-port ball valves?
The short answer: the letter describes how the ball is drilled and therefore how flow can be routed. An L-port 3-way valve diverts a common inlet to one of two outlets (a selector). A T-port 3-way valve can send flow straight through, divert it, or connect all three ports to mix or distribute. An X-port 4-way valve routes four ports in pairs and is used to reverse flow direction or circulation loops.
3-way L-port (the selector / diverter)
An L-port ball has an L-shaped bore, so it connects the common port to one of the two side ports at a time. Turn the valve and flow switches from one outlet to the other; it does not connect both outlets together.
- Use it for: directing one supply to one of two destinations, isolating one line while feeding another, simple two-way selection.
- Key point: it diverts, it does not mix. Only one outlet is fed at a time.
3-way T-port (the mixer / distributor)
A T-port ball has a T-shaped bore, which is more versatile. Depending on position it can allow straight-through flow with little pressure loss, divert to another direction, or open all three ports at once to combine or distribute flow.
- Use it for: mixing two supplies, distributing one supply to two destinations at once, or straight-through plus divert in the same valve.
- Key point: more flow combinations than an L-port, including connecting all three ports together.
4-way X-port (reverse and loop control)
A 4-way valve uses an X-drilled ball (effectively a double-L) to connect its four ports in pairs. Switching the valve swaps those pairings, which is what lets it reverse the direction of flow to and from an actuator or reverse a circulation loop.
- Use it for: reversing pump or actuator direction, switching hydraulic circulation loops.
- Key point: four ports routed in pairs; the switch reverses the flow path.
Choosing the right pattern
Start from the flow logic you need:
| You need to… | Choose |
|---|---|
| Send one supply to one of two outlets (one at a time) | 3-way L-port |
| Mix, distribute, or allow straight-through plus divert | 3-way T-port |
| Reverse direction or switch a circulation loop | 4-way X-port |
Then confirm the pressure rating, port standard, material and actuation (manual lever, or mounting for actuation) so the valve suits the circuit, not just the flow path.
The goal is the right flow path, whether you buy from us or not
We wrote this so you can pick the port pattern that does the job, L, T or X, wherever you source the valve. Start from the flow logic you need and the choice follows.
If you do want it sourced to spec, here is how we work: Velqor supplies multi-port ball valves for directing and diverting flow, in 3-way and 4-way configurations with L-port and X-port drilling, machined to your pressure and application. Tell us the flow logic, pressure rating, port standard and material, and the valve is engineered to your requirement, tested and documented. If a simpler configuration covers your need, we will say so.
Frequently Asked Questions
What does an L-port 3-way ball valve do?
An L-port valve connects a common port to one of two side ports at a time, so it diverts or selects flow between two destinations. It does not connect both outlets together, which makes it a selector rather than a mixer.
What is the difference between L-port and T-port?
An L-port only diverts flow to one outlet at a time. A T-port is more versatile: depending on position it can flow straight through, divert, or open all three ports at once to mix or distribute. Choose T-port when you need mixing or simultaneous distribution.
What is a 4-way (X-port) ball valve used for?
A 4-way X-port valve connects its four ports in pairs and swaps those pairings when switched, which lets it reverse the direction of flow to an actuator or reverse a circulation loop.
Can a 3-way ball valve mix two fluids?
A T-port 3-way valve can, because it can connect all three ports together. An L-port cannot, because it only ever connects the common port to one outlet at a time.
What else should I specify besides the port pattern?
Confirm pressure rating, port and thread standard, body material and how the valve is actuated (manual lever or a mounting pad for an actuator), so the valve suits the whole circuit and not just the flow logic.