It is very important to slowly open oil drain valves and plugs in the crankcase for which of the following reasons?
a. The oil is very hot
b. Oil can never be drained below the critical minimum level
c. Residual pressure in the crankcase may blow refrigerant vapour and oil out
d. Old oil is contaminated with refrigerant and may be very acidic
e. The oil is very cold, and may cause freeze-burns
Answer: C
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Power Engineering Chapter 121
- Oil added to refrigeration compressors
- When charging a refrigeration system it
- Charging a refrigeration system
- A sulphur candle is a test for
- Which of the following is not a recommended step for the procedure in which dry nitrogen is used for a system leak test?
- Leak testing on a refrigeration system
- Positive pressure testing of a new refrigeration system may be done
- The initial refrigerant charge is added to
- When initially charging a refrigeration system:
- The refrigerant liquid charging valve connection is:
- When using lighted sulphur candles to test for ammonia leaks in a refrigeration system, the presence of ammonia will be indicated by:
- Before operating a new refrigeration plant, or one in which piping alterations have been made, the system must be tested for:
- Which of the following is NOT a problem associated with excessive head pressure in a refrigeration plant?
- Which of the following statements about adding oil to a system is true?
- Which of the following statements about manual refrigeration system purgers is false?
- The liquid line shutoff valve of a refrigeration system is:
- What can cause a high discharge pressure in a refrigeration system?