Ingersoll Rand Minimum Pressure Valve (MPV) Kit Replacement – 70666664

Ingersoll Rand 70666664 – Minimum Pressure Valve (MPV) Kit

The Ingersoll Rand 70666664 Minimum Pressure Valve (MPV) Kit is a service and maintenance kit used in portable rotary screw compressors. The Minimum Pressure Valve controls compressed-air discharge from the separator system and maintains the minimum internal pressure required for proper compressor operation.

Working Process:

During compressor start-up, the MPV 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 system.

As the internal pressure increases and reaches the valve’s opening pressure, the MPV begins to open. Compressed air can then flow from the separator vessel toward the aftercooler and downstream air receiver or pneumatic system.

Maintaining minimum internal pressure is important in an oil-injected screw compressor because the pressure difference assists the circulation of lubricating oil through the compressor air end. The oil provides cooling, lubrication, and sealing for the screw element.

During normal loaded operation, the MPV regulates the discharge path while helping prevent the internal separator pressure from falling below the required minimum level. This supports stable oil circulation and effective air/oil separation.

The valve also provides a non-return function. When the compressor unloads or stops, the MPV closes to help prevent downstream compressed air from flowing backward into the separator and compressor circuit.

The 70666664 MPV Kit is used to restore the valve’s sealing and pressure-control performance when internal components become worn, contaminated, or damaged. The official Bobcat Portable Power listing identifies 70666664 as a Kit Minimum Pressure Valve for Portable Compressors.

During maintenance, the compressor must be shut down, isolated, and completely depressurized before the MPV assembly is serviced. The valve should be dismantled according to the applicable service procedure, and the internal components, spring, piston, seals, and valve seating surfaces should be inspected for wear, contamination, or damage.

The replacement components supplied in the kit are installed in the correct position and orientation. Proper sealing and spring operation are essential for maintaining the specified minimum pressure.

After installation, the compressor should be tested through its complete operating cycle. The MPV should remain closed during initial start-up, open at the required internal pressure, regulate discharge during operation, and close correctly 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 starting, or increased compressor operating costs.

Correct maintenance of the 70666664 Minimum Pressure Valve Kit helps maintain minimum internal pressure, support proper oil circulation and air/oil separation, prevent reverse airflow, and ensure reliable portable-compressor operation.

Part Number: 70666664
Brand: Ingersoll Rand / Doosan Portable Power
Part Description: Minimum Pressure Valve Kit (MPV Kit)
Component Type: Minimum-pressure and non-return valve service kit
Application: Portable rotary screw compressors
Primary Function: Maintains minimum internal pressure and controls compressed-air discharge
Secondary Function: Helps prevent reverse compressed-air flow
Main Benefits: Supports oil circulation, air/oil separation, pressure stability, reliable starting, and efficient compressor operation.

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