ESCO Boilers and Steam Systems

Question 1

Which steam trap failure wastes the most energy?

Accepted Answer

Failed open (blowing through)

Answer

A trap that fails open lets live steam pass straight into the condensate system, losing energy all the time. A trap that fails closed backs up condensate, which mainly causes performance and water hammer problems.

Question 2

A combustion analysis shows high O2 in the flue gas. What does that indicate?

Accepted Answer

Too much excess air, which carries heat up the stack

Answer

High flue O2 means more air than needed is entering the burner. The extra air is heated and sent up the stack, which lowers efficiency. Tuning to the right excess air level recovers that loss.

Question 3

What does a boiler stack economizer do?

Accepted Answer

Preheats feedwater using heat recovered from flue gas

Answer

A stack economizer is a heat exchanger in the flue that captures heat from the exhaust and uses it to preheat boiler feedwater, so less fuel is needed.

Question 4

Why does returning more condensate to the boiler save money?

Accepted Answer

Condensate is hot and already treated, so it cuts fuel, makeup water and chemical costs

Answer

Returned condensate holds a lot of sensible heat and is already treated water. Every gallon returned cuts heating of cold makeup water, water purchases, treatment chemicals and sewer charges.

Question 5

What is the main purpose of boiler blowdown?

Accepted Answer

Control total dissolved solids (TDS) in the boiler water

Answer

Blowdown removes water with concentrated dissolved solids to prevent scaling and carryover. Too much blowdown wastes energy, so blowdown heat recovery and automatic TDS control are common measures.

ESCO - Energy Service Company Practice Test

ESCO - Energy Service Company Practice Test

ESCO Boilers and Steam Systems