Best 3/4 Inch Air Compressor Check Valves: Top 9 Picks (October 2026)

The best 3/4 inch air compressor check valves include the R Conrader New 3/4" X 3/4" Air for female NPT inlet connections, the Generic CAC-437-2 Brass Air Compressor Check Valve for CAC-437-2 replacements, and the conrader Brass Air Compressor 3/4" Male NPT for compression tube inlets.

On this page (7 sections)

1. How we chose a 3/4 inch air compressor check valve
2. Compare 3/4 inch air compressor check valves
3. The best 3/4 inch air compressor check valves
4. How do you match a check valve to a 3/4 inch compressor?
5. Do you need an unloader port?
6. When should you choose another check valve size?
7. Which 3/4 inch air compressor check valve should you choose?

The best air compressor check valve 3/4 in for a female NPT inlet is the R Conrader tank valve, with a 3/4 in female NPT top, 3/4 in male NPT tank outlet and 1/8 in unloader port. For other setups, match the inlet style first: compression, flare and NPT are not interchangeable.

A valve can have “3/4 inch” in its name while using a different size or type at the inlet. Compare the full path from the compressor discharge tube to the tank, including any unloader connection.

For broader choices, see our Best Air Compressor Check Valve guide.

Our picks at a glance

1. 1
   Best for female NPT inlet connections

   R Conrader New 3/4" X 3/4" Air

   9.7/10 our score

   See it on Amazon
2. 2
   Best for CAC-437-2 replacements

   Generic CAC-437-2 Brass Air Compressor Check Valve

   9.6/10 our score

   See it on Amazon
3. 3
   Best for compression tube inlets

   conrader Brass Air Compressor 3/4" Male NPT

   9.4/10 our score

   See it on Amazon

4. 4

   Ei Gas Air Compressor Unloader Check Valve

   Best for continuous-run compressor systems
   Check it
5. 5

   CHECK VALVE Air Compressor in tank compressed air

   Best for flare inlets
   Check it
6. 6

   Aincix 3/4 inch Check Valve

   Best for hose-barb applications
   Check it
7. 7

   Watts LF7RU2-2 Lead-Free Brass MPT Dual Check

   Best for water-line backflow prevention
   Check it
8. 8

   Joywayus Brass Check Valve 3/4" NPT Female

   Best for female NPT general-purpose fittings
   Check it
9. 9

   GASHER 2PCS Brass Swing Check Valve 3/4"

   Best for swing-style brass valves
   Check it

How we chose a 3/4 inch air compressor check valve

The best choice depends on connection match and intended use, because the products labeled 3/4 inch here include NPT, compression, flare and general-purpose valves. We compared stated port types, unloader details and application notes.

Our score weighs specs and features against what you need when shopping for an air compressor check valve. A clear tank-valve layout ranks above a general-purpose check valve when the search is for a compressor replacement.

Compare 3/4 inch air compressor check valves

Check each inlet and outlet separately before comparing the other features. “3/4 inch” alone does not confirm that a valve will fit your compressor or tank.

The best 3/4 inch air compressor check valves

The top picks below are ordered by score, with connection style and intended use called out. The first product is for a 3/4 in female NPT inlet, while several alternatives use a different inlet type.

1

R Conrader New 3/4" X 3/4" Air: Best for female NPT inlet connections

9.7/10Our score

• 3/4 in female NPT top
• 3/4 in male NPT tank outlet
• 1/8 in unloader port
• 30 SCFM flow rate

The female NPT top and male NPT tank outlet suit a specific pair of 3/4 in connections. It also has a 1/8 in unloader port.

See it on Amazon

Pros

• Clearly stated 3/4 in NPT connection types
• Unloader port included
• 30 SCFM flow rate

Cons

• Not a match for compression or flare inlets

The R Conrader valve is the closest match when both the compressor-side fitting and the tank connection follow its specified layout. It has a 3/4 in female NPT top and a 3/4 in male NPT outlet to the tank.

The included 1/8 in unloader port may suit systems that use an unloader line. The stated flow rate is 30 SCFM, and the maximum pressure is 450 PSI.

Confirm the original valve's inlet gender and the tube or pipe connection before ordering. This is not a fit for a compression or flare inlet simply because the tank outlet is 3/4 in.

2

Generic CAC-437-2 Brass Air Compressor Check Valve: Best for CAC-437-2 replacements

9.6/10Our score

• 1/2 in NPT and 1/2 in CFPC ports
• Brass body
• Fits some named compressor models
• No unloader-side bypass hole

This CAC-437-2 replacement is for matching 1/2 in NPT and 1/2 in CFPC ports, despite the 3/4 inch title in this roundup. It is not an unloader check valve kit.

See it on Amazon

Pros

• Named replacement part number
• Brass body
• Compatibility examples are provided

Cons

• Ports are 1/2 in, not 3/4 in
• No unloader-side bypass hole

The CAC-437-2 is a specific replacement part for setups with 1/2 in NPT and 1/2 in CFPC ports. The connection sizes are smaller than 3/4 in, so this option only belongs in a 3/4 inch search when you're replacing that named part and have verified the original ports.

It is made of brass and lists a range of compatible compressor models, including IRL6560V and 5E60VAD. Its instructions specifically say it has no unloader-side bypass hole and is not an unloader check valve kit.

Use the part number and port layout to confirm fit. Don't treat this as a general 3/4 in valve based on the roundup topic.

3

conrader Brass Air Compressor 3/4" Male NPT: Best for compression tube inlets

9.4/10Our score

• 1/2 in compression top inlet
• 3/4 in male NPT tank outlet
• 1/8 in unloader port
• 20 SCFM flow rate

This Conrader valve connects a 1/2 in compression inlet to a 3/4 in male NPT tank outlet. It includes an unloader port.

See it on Amazon

Pros

• 3/4 in male NPT tank outlet
• Unloader port included
• 20 SCFM flow rate

Cons

• Top inlet is 1/2 in compression, not 3/4 in NPT

This Conrader valve connects a 1/2 in compression inlet to a 3/4 in male NPT tank outlet. It includes a 1/8 in unloader port and has a stated 20 SCFM flow rate.

Choose it when your discharge tube uses the compression connection and the tank port is male NPT. The inlet is not 3/4 in NPT, so check the tubing and original valve before assuming it matches.

The product notes that 3/4 in NPT is a nominal thread size and gives an outside measurement of 1.050 in. Use the thread standard and connection type rather than trying to identify it with a tape measure.

4

Ei Gas Air Compressor Unloader Check Valve: Best for continuous-run compressor systems

9.2/10Our score

• 3/4 in compression inlet
• 3/4 in male NPT tank outlet
• Pilot and pressure discharge functions
• Manual unloader flip valve

This combination unit joins a check valve with pilot and pressure discharge functions. Its 3/4 in compression inlet is for 3/4 in copper tubing.

See it on Amazon

Pros

• Three functions in one unit
• Manual unloader flip valve
• 3/4 in compression inlet and NPT outlet

Cons

• Not a plain 3/4 in NPT inlet check valve

The Ei valve combines a check valve with a pilot valve and pressure discharge valve. Its 3/4 in compression inlet is intended for 3/4 in copper tubing, and its outlet to the tank is 3/4 in male NPT.

The unit is factory set at 145 PSI cut-in and 175 PSI cut-out, with pressure adjustable 30–40 PSI up or down. It also has a 1/8 in NPT female port for throttle control and a manual unloader flip valve.

This is a combination valve for continuous-run compressor systems, not a plain NPT-inlet replacement. Make sure those added functions and settings suit your compressor.

5

CHECK VALVE Air Compressor in tank compressed air: Best for flare inlets

9.0/10Our score

• 3/4 in male flare top inlet
• 3/4 in male NPT tank outlet
• 1/8 in unloader port
• 30 CFM flow rate

Choose this tank check valve when the compressor line uses a 3/4 in male flare inlet and the tank uses a 3/4 in male NPT port. It includes a 1/8 in unloader port.

See it on Amazon

Pros

• 3/4 in flare inlet and NPT outlet
• Unloader port included
• 30 CFM flow rate

Cons

• Flare inlet will not match NPT or compression tubing

This tank valve has a 3/4 in male flare inlet and a 3/4 in male NPT outlet to the tank. Its 1/8 in unloader port is included, and the stated flow rate is 30 CFM.

Pick it when your compressor line uses a flare connection. A flare inlet does not match NPT or compression tubing, even though the outlet size is 3/4 in.

The valve is described with a maximum pressure of 450 PSI. Confirm the port layout on your old valve and whether your compressor needs the unloader connection.

6

Aincix 3/4 inch Check Valve: Best for hose-barb applications

8.8/10Our score

• 3/4 in non-return valve
• Hose-barb connector type
• Two valves included
• Described for marine bilge use

This two-piece 3/4 in check valve set has hose-barb connectors and is described for marine bilge use. Confirm the connection and compressor application before using it in an air system.

See it on Amazon

Pros

• Two valves in the pack
• 3/4 in size
• Hose-barb connector type

Cons

• No compressor-specific connection details

Aincix sells this as a two-piece set of 3/4 in non-return valves with hose-barb connectors. The product is described for marine bilge use, so its general check-valve purpose does not by itself guarantee a fit for a compressor tank.

Consider it only if your application calls for this connector style and the compressor maker's requirements allow it. There are no compressor-specific connection details in the product description to confirm tank compatibility.

For a tank-mounted replacement, use a valve that states the inlet, tank outlet and any unloader port you need.

7

Watts LF7RU2-2 Lead-Free Brass MPT Dual Check: Best for water-line backflow prevention

8.5/10Our score

• 3/4 in threaded connections
• Dual check design
• For residential and commercial water lines
• ANSI/ASSE Standard 1024

This 3/4 in dual check valve is described for residential and commercial water lines. Its stated application is water backflow prevention, so it is not the compressor tank pick in this group.

See it on Amazon

Pros

• 3/4 in threaded connections
• Dual check design
• Stated water-line application

Cons

• Not described as an air compressor tank check valve

The Watts LF7RU2-2 is a 3/4 in dual check valve for residential and commercial water lines. It is described for backflow prevention in plumbing, so it is not the compressor tank pick in this roundup.

Its brass construction and threaded connections may look relevant at a glance, but application matters as much as nominal size. Choose it for the stated water-line use, not as a substitute for a compressor-specific valve.

If you're comparing replacement parts for a compressor, start with its original valve connection pattern and operating needs.

8

Joywayus Brass Check Valve 3/4" NPT Female: Best for female NPT general-purpose fittings

8.3/10Our score

• 3/4 in NPT female threads
• Brass body
• Stainless steel spring
• Pack of 2

This general-purpose check valve has 3/4 in female NPT threads and comes in a two-pack. Its stated use is preventing fluid backflow, so confirm it suits your compressor before fitting it.

See it on Amazon

Pros

• Female 3/4 in NPT threads
• Two valves included
• Brass body with stainless steel spring

Cons

• Not specifically described as a compressor tank valve

Joywayus provides two brass check valves with 3/4 in female NPT threads and a stainless steel spring. Their stated purpose is to prevent backflow of fluids, so verify suitability for compressed air and your tank setup before use.

The product gives a maximum pressure rating of 200 PSI. Its female threads may be useful for a matching general-purpose connection, but they don't confirm that it includes a compressor unloader port or tank-specific design.

Compare the original part and compressor requirements before treating this as a replacement.

9

GASHER 2PCS Brass Swing Check Valve 3/4": Best for swing-style brass valves

8.0/10Our score

• Two 3/4 in female NPT swing valves
• Brass body
• Maximum working pressure 230 PSI
• Also described for air compressors

This two-pack uses a swing disc and 3/4 in female NPT connections. It is described for air compressor use, though it is a general-purpose fitting rather than a specified tank-valve replacement.

See it on Amazon

Pros

• Female 3/4 in NPT connections
• Brass swing valve
• Air compressor use is named

Cons

• Swing style may not match the original tank valve

GASHER's two-pack contains 3/4 in female NPT swing check valves made of brass. The product names air compressors among its applications and states a maximum working pressure of 230 PSI.

A swing valve uses a disc to allow flow in one direction and resist reverse flow. Check whether that valve style and pressure rating fit your compressor system, since the product is not specified as a particular tank-valve replacement.

The listed temperature range is -65°F to 250°F. Match the connections and operating requirements before choosing it.

How do you match a check valve to a 3/4 inch compressor?

Match the full connection path, not just the 3/4 in label. The inlet can be NPT, compression or flare, while the tank outlet may use a different connection type.

Write down the original valve's top connection, tank outlet, thread gender and any side port. If you need general help understanding its role, read Do You Need a Check Valve on Your Air Compressor?.

What does 3/4 inch mean on an air compressor check valve?

The 3/4 in label usually identifies a nominal connection size, not the measured outside diameter. NPT is a tapered pipe thread standard, and its outside measurement can differ from its nominal size.

Conrader notes that 3/4 in NPT measures 1.050 in across. Identify the thread standard and fitting type rather than relying on a ruler measurement alone.

Which port should you check first?

Check the inlet from the compressor discharge tube first, because the picks here use several different inlet styles. Then confirm the valve's tank outlet and any unloader port.

A valve with a 3/4 in outlet can still fail to fit if its inlet is the wrong type. Compare the labels on your original part or manual, and don't force mismatched fittings together.

Do you need an unloader port?

You need an unloader connection only if your compressor setup uses one. Several tank valves in this roundup include a 1/8 in port, while the CAC-437-2 specifically has no unloader-side bypass hole.

The unloader setup and the check valve have related jobs, but they are not the same component. If you are also comparing pressure relief parts, see our Best Air Compressor Safety Valve guide.

When should you choose another check valve size?

Choose another size when the compressor or tank connection is not a 3/4 in match. A 1 in valve may fit a larger system, while a 1/4 in valve may suit a smaller line, but the complete port layout still matters.

Compare our guides to the best air compressor check valve 1 inch and the best air compressor check valve 1/4 for those sizes. For inspection steps before replacing a part, read How To Check Air Compressor?.

Which 3/4 inch air compressor check valve should you choose?

Choose the R Conrader if you need a 3/4 in female NPT inlet, 3/4 in male NPT tank outlet and an included unloader port. Pick the Conrader compression model or the flare model when that inlet style matches your tubing, and use the Ei combination valve only when its pilot and discharge functions suit the system.

Our top 3 picks at a glance

1. 1
   Best for female NPT inlet connections

   R Conrader New 3/4" X 3/4" Air

   9.7/10 our score

   See it on Amazon
2. 2
   Best for CAC-437-2 replacements

   Generic CAC-437-2 Brass Air Compressor Check Valve

   9.6/10 our score

   See it on Amazon
3. 3
   Best for compression tube inlets

   conrader Brass Air Compressor 3/4" Male NPT

   9.4/10 our score

   See it on Amazon

Frequently asked questions

How do I choose a 3/4 inch air compressor check valve?

Match the connection at each end, including thread type, gender and tubing style. A 3/4 in tank outlet does not mean the inlet is also 3/4 in NPT.

Check the original valve and compressor manual, and confirm whether an unloader port is needed.

Does 3/4 inch NPT measure 3/4 inch across?

No. NPT sizes are nominal pipe sizes, so the measured outside diameter is not the same as the size name.

One Conrader product notes that 3/4 in NPT measures 1.050 in across.

Use the thread size and type to identify the fitting, not a ruler alone.

Do I need an unloader port on a check valve?

You need a compatible unloader setup if your compressor uses one to release pressure from the discharge line when the motor stops. Some valves include a 1/8 in unloader port, while others do not.

Check the compressor design and original valve before replacing it.

Can I use a general-purpose check valve on an air compressor?

Only if its materials, pressure rating, flow direction and connections suit the compressor application. A valve described for water, fuel or bilge use may have a different purpose or connection layout.

Match the compressor maker's requirements and the original valve.