07 Compressor Current Too Low MP4000

Occurs during pretrip (PTI) or function test only.
During compressor test, if Compressor power consumption is 25% below expected current draw or compressor phase current level differs 33% or more.
If both alarm #6 and #7 is active this indicates too high phase difference.
Expected compressor current is a function of the surrounding conditions.
Indicates:
Defective or open high pressure cutout switch.
Defective or open low pressure cutout switch or transmitter if mounted.
Defective compressor relay.
Defective volt or amp meter on power module.
Low refrigerant charge
Defective compressor.
Defective volt or amp meter on power module.
Inaccurate condenser or evaporator temperature measurement.
Defective or open compressor motor internal over temperature protection switch.

Check evaporator, condenser sensor temperatures for correct value (± 5 °C [± 9 F]) by viewing Data menu.
To determine the current draw measurement, enter Manual Function Test menu. Start and check current draw of the following components separately and together: compressor, compressor full loaded, condenser fan and evaporator fan (high or low).
Check discharge and suction pressure gauge readings.
Check power supply volts on all 3 phases.

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