Stainless Steel 3-Way Ball Valve – Manual, L-Port or T-Port, 316 CF8M, 1000 WOG, PT 1/4″–2″ (MV-3M)

Product Description

This stainless steel 3-way ball valve replaces two shut-off valves and a tee fitting with one body: divert flow between two lines with an L-port ball, or mix two streams into one with a T-port ball. Both ball types are stock builds — 3L and 3T of the same MV-3M series — in ASTM A351 CF8M, the cast form of 316 stainless steel; CF8 (cast 304) is made to order.

Sizes run 1/4″, 3/8″, 1/2″, 3/4″, 1″, 1-1/4″, 1-1/2″ and 2″ with female PT threads in stock; NPT and PF are made to order. Rated 1000 WOG with PTFE seats, −20 °C to +180 °C, for water, oil and compressed air. An ISO-style mounting pad is cast into the top, so the same valve can take a pneumatic or electric actuator later without re-piping.

Need automation now? See our pneumatic 3-way ball valve. For food and biotech lines, see the sanitary 3-way ball valve (Tri-Clamp).

T-Port vs L-Port — Which One Do You Need?

L-Port (Diverter): directs flow from the bottom port to either the left or right port (or OFF). Ideal for switching between two tanks, two pumps or two supply lines — one valve does the changeover.

T-Port (Mixer/Diverter): can connect all three ports simultaneously (mixing two lines into one), or direct flow straight through or at 90 degrees. Ideal for blending duty and bypass loops around strainers, meters or heat exchangers. Note that a T-port ball keeps at least two ports open in every handle position — it is a switching and mixing valve, not a shut-off valve; use the L-port build when you need an OFF position.

Both port types are in stock. For a full walkthrough with flow-path diagrams for every handle position, see our L-port vs T-port guide.

Key Technical Specifications

Advantages & Benefits

• System simplification: replaces multiple 2-way valves and T-fittings, reducing installation cost and space.
• Versatile flow management: mixing, diverting or isolating flow depending on the port configuration chosen.
• Actuator-ready: the ISO-style top pad means you can automate the same valve later — no re-piping.
• Corrosion resistance: 316 stainless steel with added molybdenum resists pitting from chloride-bearing media, indoors or outdoors.

Applications

A 3-way ball valve earns its place wherever an operator has to send flow one way or the other, or blend two streams. Typical duties:

• Tank-to-tank source switching (L-port): selecting which of two storage tanks feeds a line, or routing product from one tank to another, with a single valve instead of two shut-offs.
• Duty / standby pump switching (L-port): connecting either the duty or the standby pump to the downstream line, so operators can change pumps without re-piping.
• Bypass around a filter or heat exchanger (L-port): routing flow around equipment taken offline for service in general industrial plants, instead of operating several isolation valves.
• Sample and stream selection: switching between process streams to send one to a sampling point or analyser, or purging a sample line before analysis.
• Duplex strainer changeover (T-port): switching between two strainer or filter vessels so the offline side can be serviced without stopping flow.
• Hot and cold water blending (T-port): mixing two supply streams in variable proportion to hit a target outlet temperature in building HVAC and process water loops.
• Chemical blending and dispense/recirculation switching (T-port): proportioning two liquid streams, or switching a feed line between a dispense path and a recirculation loop in chemical processing.
• Compressed air routing: directing plant air to one of two downstream lines or tools, or venting one line while supplying another.

Not for potable water, fuel gas (natural gas or LPG), steam, oxygen or cryogenic service — those duties need valves certified or built for them.

FAQ

L-port or T-port — which should I choose? Choose L-port to switch flow between two destinations (two tanks, two pumps, two lines) — it diverts 90° and can also shut off. Choose T-port to mix two lines into one, run straight through, or divert to a third port. Both are in stock.

Can a 3-way ball valve shut off flow completely? The L-port ball can be rotated to an OFF position between outlets. The T-port ball keeps at least two ports connected in every position, so it switches and mixes but does not isolate — tell us your switching pattern and we will confirm the right ball and stopper configuration.

Can this valve be automated later? Yes. It has an ISO-style top mounting pad, so a pneumatic or electric actuator mounts directly. If you want it supplied automated, see our pneumatic 3-way ball valve.

Which thread standards are available? Female PT (taper) threads are in stock, sizes 1/4″–2″. NPT and PF are made to order — tell us which standard your piping uses when you request a quote.

What is the working temperature range? −20 °C to +180 °C (−4 °F to +356 °F), limited by the PTFE seats. The valve is not rated for steam service.

304 or 316 — which should I choose? The standard valve is CF8M (cast 316), in stock — its molybdenum content resists pitting from chlorides. CF8 (cast 304) is made to order for general water and air duty.

See all 3-way ball valve models — manual, pneumatic, sanitary & vacuum →