Compressor noisy

Slugging due to flood back of refrigerant

Correct piping

Do not allow more than 1/3 of systems on defrost at any time. Verify proper operation of defrost system.

Increase superheat/replace expansion valve. Correct problem/replace evaporator fan

Hydraulic knock due to excess oil in circulation.

a. Remove excess oil.

b. Recheck oil return system and pipe sizes.

Bearing damaged because of loss of oil

a. replace bearing and add oil (only after confirming)

b. Check oil return system and piping size.

c. Check or defective oil failure control.

Improper support or insulation of piping - Provide sufficient right angle bends in piping to absorb vibration and support firmly with suitable hangers

Compressor not firmly mounted - Check or loose mounts, then tight mounting bolt properly.

Unit not properly isolated or vibration pad defective. - Add vibration isolation or check for defective isolation pads

Broken connecting rod, valves or other running parts - Replace connecting rods/broken other damaged running parts