Compressor Problems And Failures

Question 1

What happens if moisture gets into the system?

Answer 1

Causes acid to form in the oil. The acid attacks the insulation on the motor windings and can cause a short circuit

Question 2

What are the causes of a compressor having low oil?

Answer 2

• low refrigerant charge or low load low mass flow of refrigerant will not return oil
• inadequate evaporator defrosting or froze evap
• short cycling of the compressor pumps oil out of the crankcase, but does not run long enough to pull it back

Question 3

What is flooding?

Answer 3

• a continuous stream of liquid refrigerant returning to the compressor
• refrigerant washes away the oil from the cylinder walls during the suction stroke without lube wearing out the cylinder walls causing blow by into crankcase
• check for proper superheat or 20 degrees farenheit system superheat at the compressor

Question 4

What is slugging?

Answer 4

• on suction cooled compressors, the effect of slugging is a more rapid process of displacing oil with refrigerant
• causes immediate compressor failure

Question 5

What kind of damage does Slugging cause on a compressor?

Answer 5

• Damaged reed valves
• damaged head gasket
• damaged connecting rods and crankshaft

Question 6

What are the causes of Slugging? And what are the cures?

Answer 6

• Refrigerant oil lying in the suction line
• Severe overcharge in a critically charged system using a fixed metering device
• the TEV is stuck open
• Check for proper superheat or use a pump down system to resolve issue

Question 7

What temperatures should a recip compressor never exceed?

Answer 7

225 - 300 degrees farenheit

Question 8

At what temps does lube oil start to lose its ability to lubricate?

Answer 8

300 - 320 degrees farenheit

350 for break down