CIRO System Operations & Maintenance

Question 1

What is the purpose of purging non-condensable gases from an ammonia system?

Accepted Answer

To remove air and other gases that reduce condenser efficiency, increase discharge pressure, and waste energy

Answer

Air and non-condensable gases accumulate in the condenser, occupying space that should be used for condensing refrigerant. This raises head pressure, reduces capacity, and increases energy consumption.

Question 2

How often should ammonia system safety valves be tested or replaced?

Accepted Answer

Relief valves must be tested or replaced at intervals specified by jurisdiction and RAGAGEP, typically every 5 years

Answer

IIAR and ASHRAE standards require periodic testing or replacement of pressure relief valves (typically every 5 years) to ensure they will open at the correct pressure in an emergency.

Question 3

What is the purpose of an oil drain on an ammonia system evaporator?

Accepted Answer

To periodically drain accumulated compressor oil from the evaporator, which reduces heat transfer efficiency when it coats tube surfaces

Answer

Oil carried into evaporators by the refrigerant accumulates on heat transfer surfaces, acting as an insulator and reducing cooling capacity. Regular oil draining maintains efficient heat transfer.

Question 4

What daily operational checks should an industrial refrigeration operator perform?

Accepted Answer

Check pressures, temperatures, oil levels, sight glasses, compressor operation, and log all readings

Answer

Daily rounds include recording suction/discharge pressures, oil pressure/level/temperature, superheat, subcooling, condenser/evaporator conditions, compressor vibration/noise, and any leaks or abnormalities.

Question 5

What is the importance of maintaining proper water treatment in evaporative condensers?

Accepted Answer

Preventing scale buildup, biological growth (Legionella), and corrosion that reduce heat transfer efficiency and system reliability

Answer

Evaporative condensers recirculate water that can develop scale, biological contamination (including Legionella), and corrosion without proper chemical treatment, all of which degrade heat transfer and can pose health risks.

CIRO - Certified Industrial Refrigeration Operator Practice Test

CIRO - Certified Industrial Refrigeration Operator Practice Test

CIRO System Operations & Maintenance