How does a screw compressor work?

A screw compressor can run loaded ('pumping air') or unloaded ('idle'). The inlet/loading valve opens and closes according to air demand. The inlet valve is controlled by a solenoid valve that supplies control air to the inlet/loading valve. Check solenoid valve coil and solenoid valve operation.

How do air compressor pressure relief valves work?

The air compressor pressure relief valve is set above the high-pressure switch and generally set at or below the vessel’s maximum operating pressure. Pressure relief valves open proportionally to the pressure increase above the setpoint, and close gradually. Safety valves open and blow off immediately upon the system pressure reaching the setpoint.

How does a pressure relief valve work?

Pressure relief valves control and limit the pressure build-up in an air compressor system. If pressure exceeds what the pressure relief valve allows, the valve will automatically open and release air until the pressure reduces. Uncontrolled pressure from an air tank or compressor can damage downstream components if the pressure gets too high.

When does a pressure relief valve open in an air compressor?

A pressure relief valve in an air compressor opens when excessive pressure builds up inside the compressor, or the valve fails. If the pressure relief valve opens when the compressor pressure exceeds the valve’s set point, it indicates it is functioning correctly.

How do I choose a pressure relief valve for an air compressor?

There are a few factors to consider when selecting a pressure relief valve for an air compressor. Choose a pressure relief valve with its set point at or below the vessel's maximum allowable working pressure (MAWP). MAWP information should be available on a tag welded to the pressure vessel.

What happens if a pressure relief valve is open?

An open relief valve can cause production loss and danger to personnel due to the flow of high-pressure air with flying debris and a dangerous sound level. Shut off the air compressor and replace the pressure relief valve before restarting it.