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Compressor discharge HP alarm on NetCol5000

Publication Date:  2019-03-06 Views:  417 Downloads:  0

Issue Description

A Netcol5000 A025 preparatory work strictly according to the user manual but when first time start the air conditioner and run less than 1 minutes it appears compressor HO switch alarm , shutdown and power off can't eliminate alarm , after a period of time appeared alarm ( HP switch locked )

Alarm Information

compressor HP switch locked

compressor HP switch alarm

Handling Process

1- As long as in diagonistic mode when compressor started , the outdoor machine rinning normally so we can exclude the outdoor unit input power lack of phase , phase error , outdoor unit switch line fault.

2- Distance between the new outdoors unti i2 1200mm and supporting feet height is 350mm , and it can meet the operation requirements of outdoor unit , so installation is not reasonable , the outdoor fan is damaged.

3- Refrigerant charging strrictly according to the manual formula calculation , it should not be the reason of charging too much refrigerant.

4- After the air condition shut down , check the exhaust pressure is 1.5Mpa but the compressor discharge HP switch trigger alarm at 4.25Mpa. eliminate alarm at 3.6Mpa.

5- Normally the HP switch is closed , when alarms it's disconnect signal , we pull out the two terminals wires of HP switch and short circuit these two wires, found the HP switch alarm is eliminated ; disconnect two terminals high-voltage switch alarm appeared again, it's shown that the HP alarm is not abnormal & at the same time use a multi-meter measured the two terminals of the HP switch .

The on-off state is off , indicating the HP switch state is normal.

6- Replace the HP switch and then restart commissioing , then A/C operation is normal.

Root Cause

HP swittch is faulty and need replacement 


Replacing the HP switch


Since the HP switch has sealant it is a must to pay attention to the removal of original HP switch.