RSES Troubleshooting 4

Question 1

A commercial refrigeration system's discharge temperature is excessively high. Which of the following is NOT a likely cause?

Accepted Answer

Low ambient temperature at the condenser

Answer

Low ambient temperature at the condenser reduces head pressure and discharge temperature, making it an unlikely cause of excessive discharge temperature.

Question 2

What symptom would a technician observe if a TXV is hunting (oscillating)?

Accepted Answer

Fluctuating suction pressure and superheat swinging above and below setpoint

Answer

A hunting TXV repeatedly over- and under-feeds refrigerant, causing suction pressure and superheat to oscillate continuously.

Question 3

A technician checks a system and finds oil in the sight glass of the liquid line. What does this indicate?

Accepted Answer

Low refrigerant charge with oil becoming visible

Answer

When refrigerant charge is low, the remaining refrigerant carries proportionally more oil, making oil visible in the sight glass.

Question 4

During a leak check using electronic leak detection, false positives are being triggered near a drain pan. What could cause this?

Accepted Answer

Cleaning solvents or certain drain pan treatments off-gassing halogen compounds

Answer

Some cleaning agents and drain pan treatments contain halogenated compounds that can trigger halide-based electronic leak detectors.

Question 5

A technician measures 0°F superheat at the suction service valve of a running system. What immediate risk does this present?

Accepted Answer

Liquid refrigerant entering the compressor, risking mechanical damage

Answer

Zero superheat means liquid refrigerant is present in the suction line, and liquid entering the compressor can cause valve and piston damage.

(RSES) Refrigeration Service Engineers Society Certification Practice Test

(RSES) Refrigeration Service Engineers Society Certification Practice Test

RSES Troubleshooting 4