NYC RMO EXAM, CHAPTER 18
(Engine Indicators) EXAM REVIEW
QUESTIONSWITH CORRECT
SOLUTIONS UPDATED 2025/2026
SYLLABUS ALREADY GRADED!!100%
GUARANTEED PASS!!!<<BRAND
NEW VERSION>>
18.1.) What type of seal is likely to be used in a midsize reciprocating compressor?
- ANSWER ✓ Mechanical
18.2.) How many bearings are needed at the shaft of a reciprocating compressor? -
ANSWER ✓ 2
18.3.) Which of the following is used to create a gas tight connection between the
valve plate, compressor head and compressor body? - ANSWER ✓ Gasket and
cement
18.4.) Which of the following is used to cool motor windings in a hermetic
compressor? - ANSWER ✓ Suction vapor
18.5.) Which of the following best describes how a "safety head" is held in place
by? - ANSWER ✓ Helical spring
18.6.) Whether it is coupled or direct connected, the shaft of the motor causes the
crankshaft of the compressor to rotate. Measured in degrees of rotation, how far
does the crankshaft turn in the time it takes one of the compressor's pistons to go
through both a suction and compression stroke? - ANSWER ✓ 360 degrees
18.7.) Which of the following describes the term "clearance vapor"? - ANSWER
✓ High pressure vapor that remains in the cylinder at the end of the compression
stroke
, 18.8.) The engine indicator diagram has a horizontal line segment that extends
from the point where the suction valve opens to the point where the compression
stroke starts. This segment represents the period during which the compressor's
cylinder is being filled with vapor. Which of the following would cause this
segment to shorten? - ANSWER ✓ Increased re-expansion
18.9.) When attempting to read the high pressure gauge on an operating ammonia
compressor, it is noted that the pointer "hunts" (has a wide and relatively slow back
and forth movement). This would most likely indicate that the compressor? -
ANSWER ✓ Valve action is sluggish
18.10.) Of the following statements, which one is correct regarding an engine
indicator diagram? - ANSWER ✓ An abnormal diagram indicates a mechanical
problem with the compressor
18.11.) What type of seal is likely to be used in a small compressor? - ANSWER
✓ Sleeve type
18.12.) A multi-cylinder, single acting compressor is equipped with reed type
compressor valves, what type of force is used to actuate these values? - ANSWER
✓ Differential pressure
18.13.) An engine indicator that is working perfectly indicates a pressure that is 20
psi below the reading of a gauge that has been installed in a system over an
extended period of time. What does the difference in readings indicate? -
ANSWER ✓ Discharge gauge is faulty
18.14.) The cylinder of a compressor is running hot at decreased capacity. Which
of the following is the most likely cause of this problem? - ANSWER ✓ Broken or
leaking piston rings
18.15.) In addition to malfunctioning compressor valves, what other component of
a compressor could affect the relative shape of an engine indicator diagram? -
ANSWER ✓ Leaking pistons
(Engine Indicators) EXAM REVIEW
QUESTIONSWITH CORRECT
SOLUTIONS UPDATED 2025/2026
SYLLABUS ALREADY GRADED!!100%
GUARANTEED PASS!!!<<BRAND
NEW VERSION>>
18.1.) What type of seal is likely to be used in a midsize reciprocating compressor?
- ANSWER ✓ Mechanical
18.2.) How many bearings are needed at the shaft of a reciprocating compressor? -
ANSWER ✓ 2
18.3.) Which of the following is used to create a gas tight connection between the
valve plate, compressor head and compressor body? - ANSWER ✓ Gasket and
cement
18.4.) Which of the following is used to cool motor windings in a hermetic
compressor? - ANSWER ✓ Suction vapor
18.5.) Which of the following best describes how a "safety head" is held in place
by? - ANSWER ✓ Helical spring
18.6.) Whether it is coupled or direct connected, the shaft of the motor causes the
crankshaft of the compressor to rotate. Measured in degrees of rotation, how far
does the crankshaft turn in the time it takes one of the compressor's pistons to go
through both a suction and compression stroke? - ANSWER ✓ 360 degrees
18.7.) Which of the following describes the term "clearance vapor"? - ANSWER
✓ High pressure vapor that remains in the cylinder at the end of the compression
stroke
, 18.8.) The engine indicator diagram has a horizontal line segment that extends
from the point where the suction valve opens to the point where the compression
stroke starts. This segment represents the period during which the compressor's
cylinder is being filled with vapor. Which of the following would cause this
segment to shorten? - ANSWER ✓ Increased re-expansion
18.9.) When attempting to read the high pressure gauge on an operating ammonia
compressor, it is noted that the pointer "hunts" (has a wide and relatively slow back
and forth movement). This would most likely indicate that the compressor? -
ANSWER ✓ Valve action is sluggish
18.10.) Of the following statements, which one is correct regarding an engine
indicator diagram? - ANSWER ✓ An abnormal diagram indicates a mechanical
problem with the compressor
18.11.) What type of seal is likely to be used in a small compressor? - ANSWER
✓ Sleeve type
18.12.) A multi-cylinder, single acting compressor is equipped with reed type
compressor valves, what type of force is used to actuate these values? - ANSWER
✓ Differential pressure
18.13.) An engine indicator that is working perfectly indicates a pressure that is 20
psi below the reading of a gauge that has been installed in a system over an
extended period of time. What does the difference in readings indicate? -
ANSWER ✓ Discharge gauge is faulty
18.14.) The cylinder of a compressor is running hot at decreased capacity. Which
of the following is the most likely cause of this problem? - ANSWER ✓ Broken or
leaking piston rings
18.15.) In addition to malfunctioning compressor valves, what other component of
a compressor could affect the relative shape of an engine indicator diagram? -
ANSWER ✓ Leaking pistons
