CFESA Steam and Water Systems 4 — Questions and Answers
Question 1: A steam kettle is producing a hammering noise during heat-up. What is the most likely cause?
- Excessive steam pressure
- Water hammer from condensate trapped in steam lines (Correct answer)
- Faulty pressure relief valve
- Clogged steam trap
Correct answer: Water hammer from condensate trapped in steam lines
Water hammer occurs when condensate accumulates in steam lines and is struck by high-velocity steam, producing a hammering or banging noise.
Question 2: What does a float-and-thermostatic (F&T) steam trap do when fully submerged in condensate?
- Opens to discharge steam
- Closes the valve to retain condensate
- Opens the valve to discharge condensate (Correct answer)
- Activates a pressure relief bypass
Correct answer: Opens the valve to discharge condensate
When the float in an F&T trap rises due to condensate accumulation, it opens the valve to discharge the condensate through the trap.
Question 3: Which type of water treatment chemical is used to prevent pitting corrosion caused by dissolved oxygen in boiler feedwater?
- Scale inhibitor
- Biocide
- Oxygen scavenger (Correct answer)
- pH buffer
Correct answer: Oxygen scavenger
Oxygen scavengers such as sodium sulfite or hydrazine chemically react with dissolved oxygen to prevent pitting corrosion in boiler systems.
Question 4: A commercial steamer's water level sight glass shows water but the unit trips on low-water cutoff. What should the technician check first?
- Thermostat calibration
- Sight glass for blockage or false reading (Correct answer)
- Steam pressure regulator
- Door gasket seal
Correct answer: Sight glass for blockage or false reading
A clogged or vapor-locked sight glass can show a false water level; the actual boiler water level may be lower than indicated.
Question 5: What is the purpose of a backflow preventer installed on the cold-water supply to a steam boiler?
- To regulate incoming water pressure
- To prevent boiler water from contaminating the potable water supply (Correct answer)
- To remove minerals from the feedwater
- To control steam pressure in the boiler
Correct answer: To prevent boiler water from contaminating the potable water supply
A backflow preventer stops potentially contaminated boiler water from siphoning back into the municipal potable water system.
Question 6: In a steam-jacketed kettle, the steam pressure in the jacket is set higher than needed. What is the most likely result?
- Faster, more even cooking with no risk
- Product scorching and potential jacket over-pressurization (Correct answer)
- Lower steam consumption
- Improved condensate drainage
Correct answer: Product scorching and potential jacket over-pressurization
Excess steam pressure raises jacket temperature above design limits, causing product scorching and risking overpressure of the jacket vessel.
Question 7: What ASME code section primarily governs the construction and inspection of commercial steam boilers used in food service equipment?
- ASME Section I — Power Boilers
- ASME Section IV — Heating Boilers (Correct answer)
- ASME Section VIII — Pressure Vessels
- ASME Section IX — Welding Qualifications
Correct answer: ASME Section IV — Heating Boilers
ASME Section IV covers the construction of heating boilers, which includes the low-pressure steam boilers commonly found in commercial food service equipment.
CFESA Steam and Water Systems 4
A steam kettle is producing a hammering noise during heat-up.
What is the most likely cause?