How do I choose the right air compressor check valve?

Match the port count, the thread size on each port and the material to the valve you're replacing. Compel lists 2 port and 3 port versions in male thread, with sizes such as 16x14mm, 20x16mm and 20x16x10mm. Check the pressure and fluid limits on the listing, because the category data doesn't state a rating.

How to tell if an air compressor check valve is bad?

Common signs are air hissing from the pump unloader after shutdown, the tank losing pressure when the compressor is off, or the pump struggling to restart. Those point to air leaking back through the valve. Confirm by listening at the valve and checking for leaks before you replace it.

Can I use a 3 port valve in place of a 2 port check valve?

Only if the system can use or safely cap the third port. A 3 port air check valve has a small side or top port, listed as 10mm on several options. If your setup has no line for it, a 2 port valve in 16x14mm or 20x16mm is the cleaner match.

Is brass or zinc alloy better for a check valve on an air compressor?

Brass is the more common choice and makes up most of the range, including the cut-off and 2 port versions. Zinc alloy is listed in selected 3 port male thread options. The data doesn't compare pressure limits, so read each listing before you decide.

Are these compressor check valves suitable for oil-free compressors?

Some listings name oil-free air compressor use directly, such as the 3-port brass option in 16x14mm and 20x16mm. Others describe use with a direct air compressor, tank and piston pump. Where the listing is silent on your machine type, confirm before fitting.

What is the most common mistake when ordering compressor check valves?

Reading thread sizes out of order. A listing such as 20mm, 19mm and 10mm, or 10x14x16 against 16x14x7, assigns each size to a specific port. Match each size to the right port on your pump, tank and side line before you order.

Compressor Check Valves

11 products available

An air compressor check valve is a one-way fitting that sits between the compressor pump and the air tank. It lets compressed air flow into the tank and stops it flowing back when the pump shuts down. Compel supplies compressor check valves to trade and industrial buyers who service, repair or build compressor systems.

TBS-08739AIRC-00007

£27.99

Brass three-port air compressor check valve with male threaded ends on a plain background

Compressor Check Valves

Air Compressor Check Valve | 3-Port Brass | 1/2" x 1/2" x 1/8" Male

TBS-08733AIRC-00005

£37.99

Which port layout does your compressor need: 2 port or 3 port?

Start with how your existing valve connects. A 2 port check valve is a straight non-return and cut-off fitting. The listed options are 16x14mm and 20x16mm male thread in brass.

A 3 port valve adds a small side or top port. Compel's listings show this as 10mm on the side port, and some valves include a cut-off function. That extra port often serves a pressure switch or unloader line, so count the lines on the valve you're replacing before you choose.

2 port: inline non-return, sizes listed as 16x14mm and 20x16mm
3 port: main inlet, tank outlet and a smaller side or top port
3 port with cut-off function: listed in brass with 10mm, 14mm and 16mm ports

How do you match thread sizes to the pump and tank?

Measure the male thread diameter on each port of the old valve, or read it from the pump and tank fittings. Listings give diameters in sequence, such as 20x16x10mm, 10x14x16, 16x14x7 or 20mm, 19mm and 10mm. Check which port each number refers to before ordering, because the same three sizes can sit in different positions.

Some listings also state a 6mm internal diameter. Use that figure if flow through the valve matters for your pump. One option is listed in imperial at 1/2" x 1/2" x 1/8" male, so don't assume every thread is metric.

Brass or zinc alloy: which material suits the job?

Most of the range is brass, in gold or nickel-plated gold finish. Brass is the usual choice for a check valve on an air compressor where the valve sees repeated pressure cycles and pump vibration. Zinc alloy options are also listed, mainly in 3 port male thread form.

The data doesn't give pressure ratings, so read the individual listing and the compressor's operating limits before you fit anything. Where a listing says oil-free air compressor, confirm that matches your machine.

Brass: widest choice across 2 port and 3 port
Zinc alloy: listed in 3 port male thread options
Aluminium: offered as a material choice on selected 3 port listings

Buying guide

Choosing Compressor Check Valves

How do I choose the right air compressor check valve?: Match the port count, the thread size on each port and the material to the valve you're replacing. Compel lists 2 port and 3 port versions in male thread, with sizes such as 16x14mm, 20x16mm and 20x16x10mm. Check the pressure and fluid limits on the listing, because the category data doesn't state a rating.
How to tell if an air compressor check valve is bad?: Common signs are air hissing from the pump unloader after shutdown, the tank losing pressure when the compressor is off, or the pump struggling to restart. Those point to air leaking back through the valve. Confirm by listening at the valve and checking for leaks before you replace it.
Can I use a 3 port valve in place of a 2 port check valve?: Only if the system can use or safely cap the third port. A 3 port air check valve has a small side or top port, listed as 10mm on several options. If your setup has no line for it, a 2 port valve in 16x14mm or 20x16mm is the cleaner match.
Is brass or zinc alloy better for a check valve on an air compressor?: Brass is the more common choice and makes up most of the range, including the cut-off and 2 port versions. Zinc alloy is listed in selected 3 port male thread options. The data doesn't compare pressure limits, so read each listing before you decide.
Are these compressor check valves suitable for oil-free compressors?: Some listings name oil-free air compressor use directly, such as the 3-port brass option in 16x14mm and 20x16mm. Others describe use with a direct air compressor, tank and piston pump. Where the listing is silent on your machine type, confirm before fitting.
What is the most common mistake when ordering compressor check valves?: Reading thread sizes out of order. A listing such as 20mm, 19mm and 10mm, or 10x14x16 against 16x14x7, assigns each size to a specific port. Match each size to the right port on your pump, tank and side line before you order.

Compressor Check Valves

Products

Air Compressor Check Valve | Brass 3-Port | 20mm Male Thread | 6mm Bore

Air Compressor Check Valve 3 Port Brass | 20mm, 19mm and 10mm Male Threads

Air Compressor Check Valve | Brass Inline | G1/8 to G3/4 Female Thread

Air Compressor Check Valve | 3-Port Brass Male Thread | 16x14mm, 20x16mm

Air Compressor Check Valve | 3-Port Brass | 10, 16, 20mm Male Thread

Air Compressor Check Valve | 2 Port Brass Male Thread | 16x14mm or 20x16mm

Air Compressor Check Valve | Brass 3-Port | 6mm Bore | Male Thread

Air Compressor Check Valve | 3 Port Male Thread | Brass, Zinc or Aluminium

Air Compressor Check Valve | 3 Port Brass | 10mm 14mm 16mm Ports

Air Compressor Check Valve | 3-Port Male Thread | 10x14x16, 16x14x7 Options

Air Compressor Check Valve | 3-Port Brass | 1/2" x 1/2" x 1/8" Male

Which port layout does your compressor need: 2 port or 3 port?

How do you match thread sizes to the pump and tank?

Brass or zinc alloy: which material suits the job?

Choosing Compressor Check Valves