CFESA Repair Techniques 3 — Questions and Answers
Question 1: When repairing a commercial walk-in cooler door that will not seal properly, which component should be inspected first?
- The evaporator fan motor
- The door gasket and cam-lift hinge adjustment (Correct answer)
- The condenser coil fins
- The defrost timer setting
Correct answer: The door gasket and cam-lift hinge adjustment
A worn or misaligned gasket and improper cam-lift hinge adjustment are the primary causes of poor door sealing on walk-in coolers.
Question 2: A commercial griddle has one heating zone that does not reach setpoint while adjacent zones operate normally. The most likely cause is:
- A failed thermostat for that zone only (Correct answer)
- Low gas supply pressure to the entire unit
- A clogged grease drain
- A misaligned pilot orifice
Correct answer: A failed thermostat for that zone only
Independent zone thermostats control each section; failure of one thermostat causes only that zone to underperform while adjacent zones remain unaffected.
Question 3: Which repair method is recommended when re-seating a commercial refrigeration compressor to reduce vibration transmission?
- Bolt the compressor directly to the frame without isolation
- Install rubber vibration isolators between the compressor feet and mounting bracket (Correct answer)
- Weld the compressor feet to the base
- Use plastic spacers between compressor and frame
Correct answer: Install rubber vibration isolators between the compressor feet and mounting bracket
Rubber vibration isolators absorb compressor vibration, preventing structural noise and fatigue cracks in refrigerant lines.
Question 4: A technician is repairing a commercial char-broiler where one burner section has a yellow, lifting flame. After ruling out gas pressure issues, what should be inspected?
- The burner orifice for enlargement or debris blockage (Correct answer)
- The igniter electrode gap
- The thermocouple millivolt output
- The burner grate alignment
Correct answer: The burner orifice for enlargement or debris blockage
A yellow or lifting flame on a single burner section typically indicates a blocked or damaged orifice affecting the air-to-gas mixture.
Question 5: When rebuilding a commercial high-pressure pump on a steam cleaning unit, which seal material is appropriate for use with high-temperature water?
- Standard nitrile (Buna-N) seals
- EPDM or PTFE seals rated for high temperature and water service (Correct answer)
- Silicone grease-lubricated leather seals
- Standard neoprene seals
Correct answer: EPDM or PTFE seals rated for high temperature and water service
EPDM and PTFE seals are specifically rated for high-temperature water service and resist degradation that would affect nitrile or neoprene.
Question 6: A commercial combi-oven displays an error for high steam chamber pressure. After verifying the drain is clear, what component should be inspected?
- The magnetron assembly
- The steam generator pressure relief valve and pressure transducer (Correct answer)
- The convection fan belt
- The door hinge spring tension
Correct answer: The steam generator pressure relief valve and pressure transducer
A stuck-closed pressure relief valve or faulty pressure transducer can cause false or actual over-pressure conditions in the steam chamber.
Question 7: When replacing a shorted heating element in a commercial hot food holding cabinet, what must be verified about the replacement element before installation?
- That it matches in wattage, voltage rating, and physical dimensions (Correct answer)
- Only that the physical dimensions match
- Only that the wattage matches
- That it is the same brand as the original
Correct answer: That it matches in wattage, voltage rating, and physical dimensions
The replacement element must match wattage, voltage rating, and physical dimensions to ensure proper heating performance and safe fit.
CFESA Repair Techniques 3
When repairing a commercial walk-in cooler door that will not seal properly, which component should be inspected first?