DC BOILER COMPREHENSIVE
EXAMINATION GUIDE 2026 FULL Q&A
STUDY SET
◉ Why add phosphates to boiler water?.
Answer: Converts scale forming salts to non-adhering sludge
◉ Excess oxygen present bin the boiler water would be a direct
indication of?.
Answer: Improper operation of the dearating feedwater tank
◉ Cheleants do what when added to boiler water?.
Answer: Convert calcium, magnesium, and iron to non-adhering
sludge
◉ What two compounds are used as oxygen scavengers in boilers?.
Answer: Sodium sulfite & Hydrazine
◉ Entrained oxygen in feedwater entering the boiler will cause ___?.
Answer: Localized pitting
, ◉ What type of waterside deposits are removed by boiling out a
boiler?.
Answer: oil & grease
◉ What are the most common gases which become dissolved in the
boiler water and will cause corrosion in the internals of the boiler?.
Answer: Oxygen and Carbon Dioxide
◉ What effect does temperature and pressure have on the activity of
oxygen entrained in boiler feedwater?.
Answer: Oxygen is less active with high temperatures and pressures
◉ Define titration.
Answer: A procedure of neutralizing an unknown solution with a
reagent of a known quantity
◉ The three basic classifications of impurities found in natural
water are?.
Answer: dissolved solids, dissolved gasses, suspended solids
◉ What is the condition in which boiler metal becomes too brittle
because of crystalline cracking?.
Answer: Caustic embrittlement
EXAMINATION GUIDE 2026 FULL Q&A
STUDY SET
◉ Why add phosphates to boiler water?.
Answer: Converts scale forming salts to non-adhering sludge
◉ Excess oxygen present bin the boiler water would be a direct
indication of?.
Answer: Improper operation of the dearating feedwater tank
◉ Cheleants do what when added to boiler water?.
Answer: Convert calcium, magnesium, and iron to non-adhering
sludge
◉ What two compounds are used as oxygen scavengers in boilers?.
Answer: Sodium sulfite & Hydrazine
◉ Entrained oxygen in feedwater entering the boiler will cause ___?.
Answer: Localized pitting
, ◉ What type of waterside deposits are removed by boiling out a
boiler?.
Answer: oil & grease
◉ What are the most common gases which become dissolved in the
boiler water and will cause corrosion in the internals of the boiler?.
Answer: Oxygen and Carbon Dioxide
◉ What effect does temperature and pressure have on the activity of
oxygen entrained in boiler feedwater?.
Answer: Oxygen is less active with high temperatures and pressures
◉ Define titration.
Answer: A procedure of neutralizing an unknown solution with a
reagent of a known quantity
◉ The three basic classifications of impurities found in natural
water are?.
Answer: dissolved solids, dissolved gasses, suspended solids
◉ What is the condition in which boiler metal becomes too brittle
because of crystalline cracking?.
Answer: Caustic embrittlement
