Atlas Copco Minimum Pressure Valve (MPV) Kit Replacement – 2901145300

Atlas Copco 2901145300 – Minimum Pressure Valve (MPV) Kit

The Atlas Copco 2901145300 (2901-1453-00) Minimum Pressure Valve Kit is a service and maintenance kit used in oil-injected rotary screw compressors. The Minimum Pressure Valve controls compressed-air discharge from the separator circuit while maintaining the minimum internal pressure required for proper compressor operation.

Working Process:

During compressor start-up, the Minimum Pressure Valve remains closed or highly restricted. This allows pressure to build inside the air/oil separator vessel and compressor circuit before compressed air is supplied to the downstream air network.

As the internal pressure rises and reaches the valve’s required opening pressure, the MPV begins to open. Compressed air can then pass from the separator vessel toward the aftercooler and downstream compressed-air system.

Maintaining minimum internal pressure is important in an oil-injected screw compressor because the pressure difference supports the circulation of compressor oil through the air end. The oil performs essential functions including lubrication, cooling, and sealing of the screw element.

During loaded operation, the MPV remains open while controlling the discharge path and helping maintain sufficient pressure within the separator circuit. This supports stable oil circulation and effective oil separation from the compressed air.

The valve also provides an important non-return function. When the compressor unloads or stops, downstream pressure can remain higher than the pressure inside the compressor. The MPV closes to help prevent compressed air from flowing backward into the separator and compressor circuit.

The 2901145300 service kit restores the valve’s sealing and pressure-control performance when internal components become worn, contaminated, or damaged. Atlas Copco officially identifies the part as “KIT VALVE MINIMUM PRESSURE FOR OIL INJECTED SCREW COMPRESSOR.” The official specification lists a weight of 139 g.

The official component list includes O-rings, springs, piston valve, retaining ring/circlips, grease, and minimum-pressure-valve components. These parts restore the valve’s internal movement and sealing capability during servicing.

During maintenance, the compressor must be stopped, isolated, completely depressurized, and allowed to cool before the MPV assembly is serviced. The valve body, piston, springs, seals, retaining components, and internal passages should be inspected for wear, contamination, corrosion, or damage.

The old sealing components should be replaced with the correct components supplied in the 2901145300 maintenance kit. The piston and spring must be installed in the correct orientation so that the valve opens and closes at the required pressure.

After reassembly, the compressor should be tested through its complete operating cycle. The MPV should allow pressure to build during start-up, open correctly at the specified pressure, maintain stable internal pressure during loaded operation, and close effectively during unloading and shutdown.

A worn or malfunctioning MPV can cause slow pressure build-up, unstable discharge pressure, poor oil circulation, excessive oil carryover, reverse airflow, difficult restarting, air leakage, or increased energy consumption.

If the valve remains open or leaks, the compressor may lose internal pressure and compressed air may flow incorrectly through the system. If the valve remains closed, excessive internal pressure can develop and restrict normal compressed-air delivery.

Correct maintenance using the 2901145300 Minimum Pressure Valve Kit helps maintain minimum compressor pressure, support proper oil circulation and air/oil separation, prevent reverse pressure flow, reduce leakage, and ensure reliable compressor operation.

Part Number: 2901145300
Alternative Number: 2901-1453-00 / 2901 1453 00
Brand: Atlas Copco
Part Description: Kit Valve Minimum Pressure / Minimum Pressure Valve Kit
Component Type: Minimum-pressure and non-return valve service kit
Application: Oil-injected rotary screw compressors
Known Applications: Commonly listed for GA-series compressors, including GA55, GA75, GA90, GA75 VSD and GA90 VSD configurations.
Official Listed Weight: 139 g
Primary Function: Maintains minimum internal compressor pressure
Secondary Function: Prevents reverse compressed-air flow
Main Components: Piston valve, springs, O-rings, retaining components, grease and valve service components
Main Benefits: Stable pressure, proper oil circulation, effective air/oil separation, reduced leakage, reliable starting, and efficient compressor operation.

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