CIRO System Operations & Maintenance 2 — Questions and Answers
Question 1: What causes high discharge pressure in a compressor?
- Dirty condensers, non-condensable gases, excessive refrigerant charge, high ambient temperature, or restricted condenser airflow (Correct answer)
- The system is working perfectly
- Low refrigerant charge
- Underloaded evaporators
Correct answer: Dirty condensers, non-condensable gases, excessive refrigerant charge, high ambient temperature, or restricted condenser airflow
High discharge (head) pressure results from anything that impairs heat rejection in the condenser: fouled surfaces, air in the system, overcharge, restricted airflow, high ambient temperatures, or faulty condenser fans.
Question 2: What causes low suction pressure in a compressor?
- Low refrigerant charge, restricted liquid line, dirty evaporator, low airflow across evaporator, or a stuck expansion valve (Correct answer)
- Excess refrigerant in the system
- High ambient temperature
- The compressor is too small
Correct answer: Low refrigerant charge, restricted liquid line, dirty evaporator, low airflow across evaporator, or a stuck expansion valve
Low suction pressure indicates insufficient refrigerant reaching the evaporator: possible causes include leak (low charge), restriction in the liquid line, fouled evaporator coils, inadequate air/fluid flow, or expansion valve malfunction.
Question 3: What is the purpose of a vibration isolation system for compressors?
- To prevent compressor vibration from transmitting to the building structure, piping, and equipment, reducing noise and preventing fatigue failures (Correct answer)
- To increase compressor speed
- To improve refrigerant flow
- To reduce electrical consumption
Correct answer: To prevent compressor vibration from transmitting to the building structure, piping, and equipment, reducing noise and preventing fatigue failures
Vibration isolators (spring mounts, rubber pads, flexible piping connections) prevent mechanical vibration from the compressor from damaging piping connections, building structures, and nearby equipment.
Question 4: What is a Management of Change (MOC) procedure?
- A systematic process for evaluating and documenting any modifications to equipment, procedures, or materials before implementation to prevent introducing new hazards (Correct answer)
- A procedure for changing employee shifts
- A method for changing refrigerant types
- A process for updating the company logo
Correct answer: A systematic process for evaluating and documenting any modifications to equipment, procedures, or materials before implementation to prevent introducing new hazards
MOC is a PSM requirement ensuring that any change to the refrigeration system (equipment modifications, procedure changes, material substitutions) is evaluated for safety implications before implementation.
Question 5: What is a Mechanical Integrity (MI) program?
- A systematic program of inspections, testing, and maintenance to ensure that process equipment operates safely and reliably (Correct answer)
- A software for tracking equipment warranties
- A program for replacing all equipment annually
- An exercise program for maintenance workers
Correct answer: A systematic program of inspections, testing, and maintenance to ensure that process equipment operates safely and reliably
MI programs include documented inspection schedules, pressure vessel testing, piping inspections, safety device testing, equipment maintenance procedures, and quality assurance for repairs and replacements.
Question 6: What records must an industrial refrigeration operator maintain?
- Operating logs, maintenance records, inspection reports, PSM/RMP documentation, training records, and incident reports (Correct answer)
- Only payroll records
- No records are required for operators
- Only annual inspection reports
Correct answer: Operating logs, maintenance records, inspection reports, PSM/RMP documentation, training records, and incident reports
Comprehensive recordkeeping is required for regulatory compliance (PSM/RMP) and good operating practice: daily operating logs, maintenance history, inspection results, training documentation, emergency response drills, and incident investigations.
CIRO System Operations & Maintenance 2
What causes high discharge pressure in a compressor?