Boilers

Question 1

List the boiler trips?

Answer 1

• High steam pressure trip
• Low water level trip
• Flame failure trip
• High furnace pressure
• High fuel oil temp
• High exhaust temp
• Low fuel pressure

Question 2

Explain boiler safety features and systems?

Answer 2

• The safety pressure relief valve will lift at 103%
• The automatic water level controller will regulate water flow
• Flame monitor
• Emergency shut downs

Question 3

Explain calorifier maintenance?

Answer 3

• Visual inspections
• Cleaning and descaling any scale, sediments and mineral deposits built up on the walls and heating elements
• Sacrificial anode rods
• Temperature and pressure testing

Question 4

What tests would be completed?

Answer 4

• Chlorides Tests
• Phosphate reserve
  -Alkalinity to Phenolphthalein
• Hydrostatic pressure test, water is filled to 150% of working pressure
• Safety relief valve test
• Water control tests
• Flame detector test
• Safety interlock tests
• Emergency stop test

Question 5

Describe furnace cut out / flame detector?

Answer 5

It is a critical safety device. As soon as it senses there is no flame by using infrared detection, it will alarm and stop the supply of fuel being sprayed into the boiler

Question 6

Cause of low water alarm?

Answer 6

• Loos of feed water, this could be a pump failure, valve failure or a blockage
• Leakage from a fitting
• Failure of water level sensor
• Foaming due to impurities giving a reading of more water than there is

Question 7

What do you do if calcium builds up in the water?

Answer 7

• Add a chemical treatment
• Blow down the boiler regularly
• Isolate the boiler and manually clean the tubes

Question 8

What care and management of auxiliary boilers?

Answer 8

• Regular inspection
• Record keeping
• Water tests/ treatment
• Acid cleaning
• Test safety devices
• Correct operation (Don’t run dry)
• Train crew

Question 9

Explain construction?

Answer 9

Pressure vessel - cylindrical and high quality steel
Water tubes - Arranged in bank for max heat transfer and stainless steel
Burner - Provide Diesel or HFO
Combustion chamber
Steam drum - Holds steam and water above the water tubes
Economizer - exhaust system which heats the feed water, reducing waste heat
Safety devices
Insulation to reduce heat loss

Question 10

Explain blowing down sight glass?

Answer 10

• Shut the steam and water chocks
• Open the drain cock, watch for condensate and the flow to stop.
• Open water cock and check flow then shut
• Open steam cock and check flow then shut
• Shut drain cock
• Open water cock and fill to the top
• Open steam cock and watch water level return to working level in boiler

Question 11

Explain chemical cleaning?

Answer 11

A diluted acid solution is circulated through the boiler to dissolve and remove scale build up

Question 12

Why is the alkalinity important?

Answer 12

Alkalinity is a critical parameter in boiler water chemistry that influences corrosion control, scale prevention, steam quality, and water treatment effectiveness

Question 13

How would you check the level if both sight glasses were scaled up and no remote indication?

Answer 13

Firstly I wouldn’t get it get this far. But sight glasses glass can be changed.

I would try a blow down procedure.

If still scaled, I would isolate the cocks on the steam and water then change the glass

Question 14

No suction on PD pump, No suction on centrifugal pump?

Answer 14

PD - sucking air, needs priming or blockage

Centrifugal - damaged impeller, needs priming, blockage or cavitation

Question 15

How often do you test the water and why?

Answer 15

Weekly water tests

• Ensure the water quality is correct
• Protect against scale
• Protect against corrosion
• Ensure steam quality