A reciprocating air compressor is a positive displacement mechanical device that\u00a0uses a\u00a0cylinder and crankshaft-driven piston to produce compressed air. An unloader valve is\u00a0a small and essential\u00a0part\u00a0that\u00a0ensures\u00a0the effective, efficient operation of a reciprocating compressor.<\/p>\n
A compressor unloader valve is a small part, usually sized between 4 and 5 inches. The valve releases trapped air from inside the compressor’s tank, which allows the motor to restart. If the unloader valve cannot release the air, the built-up pressure might prevent the motor from starting.<\/p>\n
An air compressor’s valve type\u00a0depends on the machine\u2019s make and size. Some operate via a toggle switch on the side of the unit\u2019s pressure switch. Others have an integral valve installed under the pressure switch.<\/p>\n
During the operation of a typical reciprocating air compressor, the machine\u2019s electric motor-driven tank fills with air. The device contains a pressure switch that responds to\u00a0air\u00a0accumulation by shutting off the motor\u2019s power supply. The compressor pump, which is attached to the motor shaft, also stops.<\/p>\n
When the motor\u00a0tries\u00a0to restart,\u00a0the trapped air produces\u00a0a load that\u00a0restricts its ability to switch on.\u00a0By venting the air, the unloader valve\u00a0minimizes\u00a0the load\u00a0across\u00a0the piston,\u00a0which encourages\u00a0the\u00a0repowering\u00a0process.<\/p>\n
Unloader valves are located on top of or inside the pressure switch in smaller reciprocating air compressors.\u00a0When the switch shuts the compressor off, it actuates the valve. A small tube or pipe runs from the check valve\u00a0\u2014\u00a0a device that keeps the entire tank from draining\u00a0\u2014\u00a0to the unloader valve.<\/p>\n
A larger air compressor\u00a0usually contains a larger\u00a0unloader valve.\u00a0It’s controlled by air pressure that’s released from a smaller pilot valve.\u00a0In this arrangement, the valve typically sits next to the compressor.<\/p>\n
When the air pressure within the compressor tank arrives at the point where it cannot deliver any more air, the valve switch automatically disrupts the power supply to the motor. After the power supply turns off, the unloader valve opens and vents the accumulated air.<\/p>\n
When the tank pressure drops back down to the predetermined setting on the pressure switch, it causes the switch to trip again. This action results in the release of the unloader valve\u2019s pin, preventing the escape of compressed air into the atmosphere.<\/p>\n
A malfunctioning unloader valve is one of the most common issues that prevents a compressor from operating properly. When the air cannot escape from the tank, the built-up pressure often hinders the unit\u2019s ability to restart.<\/p>\n
When the unloader valve malfunctions, it becomes unable to open or close. Open valves release a continuous stream of leaking air. Closed valves result in significant pressure buildups that can restrict the pump’s internal components. When the interior components can’t move, this prevents the engine shaft from opening.<\/p>\n
You should replace faulty unloader valves as soon as possible before they impact other critical compressor components. Learn more about how to replace an unloader valve below.<\/p>\n
Find a Dealer<\/a><\/p>\n Various air compressors have different types of unloader valves. Whether you’re working with a toggle switch on the side of the pressure controller or a valve that mounts directly to the unit, both types require the same materials for replacements:<\/p>\n First, open the drain valve to depressurize the tank. After the pressure releases, identify the unloader valve. It’s connected to a hose that transfers water to the recirculation pump.<\/p>\n Next, it’s time to remove the old valve. Follow these steps:<\/p>\n After removing the old valve, you can install the new one with these instructions:<\/p>\n A new unloader valve can save you significant time and expenses. Proper maintenance steps protect your compressor components from excessive repairs.<\/p>\n The air experts at Quincy Compressor can assist with any questions about unloader valves and replacements.\u00a0Connect with us online<\/a>\u00a0today to learn more.<\/p>\nWhat You Need to Get Started<\/h3>\n
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Unloader Valve Replacement Steps<\/h3>\n
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Find Reciprocating Compressor Unloader Valve Parts at Quincy Compressor<\/h2>\n