132 Questions
What is the primary concern when starting a boiler from cold?
Adhering to boiler warm-up rates prescribed by manufacturers
What should an operator do if abnormal conditions occur during the light-off or warm-up period?
Shut down the boiler immediately and close the main and pilot test firing valves
Why do new hazards appear during startup of a boiler plant?
Because of the rapid changes in plant conditions and related hazards
What is the purpose of the recommended boiler warm-up rates?
To prevent leaks and premature boiler failure
What is the recommended course of action after identifying the cause of trouble during startup?
Correct the problem before restarting the boiler
What is the primary objective of the recommended procedures for boiler startup?
To ensure the safety and long life of boilers
What is the main cause of thermal shock in metal?
Sudden change in temperature
What is the effect of thermal shock on boiler tubes?
Formation of tiny cracks in the tubes
What is a normal condition during the warm-up period of a cold oil-fired boiler?
Slight smoking
Why is it important to warm up boilers slowly?
To prevent thermal shock
What may occur when a cold boiler is first started, especially in firetube boilers with large water content?
Flue gas condensation
What is the result of rapid heating during a cold start in firetube boilers?
Thermal shock and refractory damage
What is the maximum recommended temperature increase per hour for boiler water?
55°C per hour
What is the purpose of ensuring the atomizing air or steam is at the correct pressure during a cold start?
To ensure complete combustion
What is the purpose of bypassing part of the flow around the boiler in a hot water heating system?
To prevent thermal shock
What is the effect of cold make-up water on steam boilers?
It causes thermal shock
What is the effect of scale buildup on the furnace and firetubes during a cold start?
It insulates the furnace tube and firetubes from the cooling effect of the boiler water
What should be done if a boiler continues to smoke after being warmed up?
Take the burner out of service
What is the recommended firing rate after ignition?
Manual low-fire control
What is the main factor affecting the rate at which a boiler can be brought up to its normal operating temperature and pressure?
All of the above
What is the effect of high firing rates during a cold start in firetube boilers?
Rapid heating and uneven expansion
Why is it important to keep make-up water sources at normal operating temperature?
To prevent thermal shock
What is the consequence of uneven expansion in firetube boilers during a cold start?
Premature boiler failure and costly repairs
What should be checked if a boiler is still smoking after the warm-up period?
All of the above
What is the purpose of the water level control system in steam boilers?
To monitor water level
What is the result of a heavily smoking burner receiving additional combustion air?
An explosive condition
What is the primary purpose of checking the furnace draft pressures during boiler startup?
To verify that combustion gases are passing normally through the furnace and flue gas passages
What is the recommended action if the boiler has a continuous pilot?
Allow at least 5 minutes for the furnace to purge naturally with the pilot and main gas valves shut
What is the purpose of reviewing the manufacturer recommendations for burner and boiler startup?
To follow the specific startup procedures for the boiler
What is the purpose of the boiler control switch?
To turn the boiler on or off
What should the Power Engineer do after boiler pressure approaches its normal pressure or temperature set point?
Switch the firing rate control to automatic
What is the purpose of the furnace purge during boiler startup?
To remove any combustible gases from the furnace
What should the Power Engineer do if the boiler has a gas-fired atmospheric burner and a continuous pilot?
Allow at least 5 minutes for the furnace to purge naturally with the pilot and main gas valves shut
Why is it important to monitor the boiler during its warm-up period?
To intervene if necessary to prevent accidents or damage
What should the Power Engineer do before starting the boiler?
Prepare the boiler plant auxiliaries according to site-specific procedures
What is the purpose of the daily log during boiler startup?
To enter a summary of the startup events
What is the purpose of purging the boiler for a given time period?
To remove any air from the combustion chamber
What should be done during the main burner ignition trial?
The main burner safety shut-off valves should open
Why should the boiler be fired at low fire during warm-up?
To limit the differential expansion between the furnace tube and firetubes
What should be checked frequently during the warm-up process?
The boiler for leaks
What should be done when the burner shuts down?
The water pressure on the tridicator gauge should be checked
What is the purpose of the try lever and pop tests?
To check the safety relief valve for evidence of leaking
What should be done when cutting in a hot water boiler in a multiple boiler plant?
The valve in the connecting line between the boiler and the tank should be closed
Why should the boiler be warmed up slowly?
To limit the differential expansion between the furnace tube and firetubes
What should be done with the stop valves in the supply and return lines to the boiler during warm-up?
They should be closed
What should be entered in the log book after startup?
The date and time of startup
What is the main reason to ensure sufficient space in the expansion tank during warmup?
To accommodate the expanded water produced during warmup
What should be done when the stop valve at the boiler outlet is closed?
Close the valve in the return line
How should the stop valve on the boiler outlet be opened when the boiler water reaches the supply main temperature?
Open the valve slowly until it is fully open
What is the purpose of cracking open the outlet valve during the alternative warmup method?
To establish flow through the cold boiler without causing shock
Why is it important to plan ahead for heating loads?
To ensure the on-line boilers have sufficient capacity to heat the extra boiler
What is the purpose of the furnace purge during the safe startup of a steam boiler?
To purge the furnace of combustible gases
What is the recommended approach to warming up steam lines and headers?
Simultaneously with the boiler
What is the purpose of the block valve at the outlet of the boiler?
To isolate the boiler from the steam header
What happens when steam enters the cold steam piping during warmup?
It condenses heavily at first, but decreasingly as the steam piping comes up to temperature
Why is it essential to warm up the steam header with the boiler stop, header stop, and drain valves open?
To ensure the steam piping and boiler warm and pressurize at the same rate
What is the purpose of opening the main steam shutoff valve during the simultaneous warm-up procedure of a steam boiler and its steam piping?
To permit the flow of steam into the steam piping
Why is it important to open the boiler drum vent during the warm-up procedure?
To release corrosive dissolved gases from the boiler water
What is the recommended firing rate during the initial warm-up period of a steam boiler?
Low fire
What is the purpose of inspecting the boiler frequently during the warm-up period?
To check for leakage at washout plugs, valves, handholes, and pipe connections
When should the superheater vent be closed during the warm-up procedure?
When adequate flow of superheated steam is established
What is the purpose of closing the low point drains during the warm-up procedure?
To prevent excessive steam from blowing from the drains
When should the main disconnect switch be closed during the warm-up procedure?
When the pilot flame is established
What is the purpose of reviewing manufacturer recommendations for burner and boiler startup during the warm-up procedure?
To ensure the correct sequence of startup
Why is it important to open the trap bypasses during the warm-up procedure?
To allow the release of condensate from the steam piping
What is the purpose of performing operating control and safety limit checks during the warm-up procedure?
To verify the proper operation of the boiler controls and safety limits
During the startup of a boiler, what is a significant challenge to a Power Engineer’s knowledge and skills?
Identifying and addressing changing hazards
What is the primary reason operators need to pay attention to boiler warm-up rates during startup?
To prevent boiler failure and ensure safety
If abnormal conditions occur during the light-off or warm-up period, what should the operator do?
Shut down the boiler immediately and close the main and pilot test firing valves
Why is it important to correct the problem before restarting the boiler after an abnormal condition occurs?
To prevent further damage to the boiler
What is the primary concern during the boiler startup process?
Ensuring safety and preventing accidents
Why is it essential to monitor the boiler during its warm-up period?
To prevent boiler failure and ensure safety
What is the primary cause of thermal shock in boilers?
Rapid temperature changes
What should be done to prevent thermal shock when starting a cold boiler?
Gradually warm up the boiler to prevent rapid temperature changes
What is the recommended maximum temperature increase per hour for boiler water?
55°C
What can cause thermal shock in steam heating boilers?
Cold make-up water
Why is it important to keep boilers free from scale buildup?
To prevent thermal shock
What is the result of rapid temperature changes in boilers?
Thermal shock and internal stress
What should be done to protect a boiler from uneven expansion and thermal shock?
W warm up the boiler slowly
What is the effect of thermal shock on boiler tubes?
Formation of tiny cracks in the metal
Why is it important to warm up boilers slowly?
To prevent thermal shock and uneven expansion
What is the primary concern when starting a boiler from cold?
Thermal shock and uneven expansion
Why does condensation occur in firetube boilers during the cold start?
When the water vapour in the flue gases contacts the cold heating surfaces of the boiler
What is the result of uneven expansion in firetube boilers during a cold start?
The tubes and furnace expansion is restricted, causing localized stress on the tube sheets
Why is it important to avoid high firing rates during a cold start in firetube boilers?
To prevent thermal shock and refractory damage
What is the recommended action if the burner continues to smoke after being warmed up?
Take the burner out of service and ensure the burner nozzle is clean and properly assembled
Why is it important to avoid adding additional combustion air to a heavily smoking burner?
To prevent the formation of explosive conditions
What is the effect of scale buildup on the furnace and firetubes during a cold start?
It insulates the furnace tube and firetubes from the cooling effect of the boiler water
What is the purpose of ensuring the atomizing air or steam is at the correct pressure during a cold start?
To ensure complete combustion and reduce smoking
Why is it important to warm up a cold oil-fired boiler slowly?
To prevent thermal shock and refractory damage
What occurs when the water vapour in the flue gases contacts the cold heating surfaces of the boiler during a cold start?
The water vapour condenses, causing condensation
What is a normal condition during the warm-up period of a cold oil-fired boiler?
Slight smoking from the stack
What is the primary purpose of checking the furnace draft pressures during boiler startup?
To ensure the combustion gases are passing normally through the furnace and flue gas passages
What should the Power Engineer do before starting the boiler?
Review the manufacturer's recommendations for burner and boiler startup
What is the purpose of purging the boiler for a given time period during the startup procedure?
To allow for four combustion chamber air changes
What should be done when cutting in a hot water boiler in a multiple boiler plant?
Raise the pressure to at least the minimum required static pressure for the cold system
Why is it essential to monitor the boiler during the warm-up period?
To prevent the boiler from being left unattended during its warm-up period
What is the purpose of the boiler control switch?
To turn the boiler on or off
Why is it important to warm up the boiler slowly?
To prevent thermal shock and stress on the boiler metal
What should be done when the boiler pressure approaches its normal pressure or temperature set point?
Switch the firing rate control to automatic
What should be done during the main burner ignition trial?
The main burner safety shut-off valves should be opened
What should be checked frequently during the warm-up process?
The burner operation and leaks
What is the purpose of the furnace purge during the safe startup of a hot water boiler?
To allow the furnace to purge naturally with the pilot and main gas valves shut
What is the recommended approach to starting a hot water boiler in a single boiler plant?
To prepare the boiler plant auxiliaries according to site-specific procedures
What is the purpose of the try lever and pop tests?
To check the safety relief valve
What should be done if the flame at low fire provides insufficient heat to reach normal operating temperature after 30 minutes?
Gradually increase the firing rate using the manual firing rate control
What is the purpose of reviewing the manufacturer's recommendations for burner and boiler startup?
To follow the recommended procedures for startup to ensure safe and proper operation
What is the purpose of raising the water temperature slowly during the warm-up process?
To ensure the entire water content of the system and boiler is warmed prior to increasing fuel input
What should the Power Engineer do after the boiler has been started?
Enter a summary of the startup events in the daily log
Why is it important to ensure the boiler is properly maintained during the warm-up period?
To prevent thermal shock and uneven expansion in the boiler
What should be done after the boiler pressure approaches its normal pressure or temperature set point?
Enter the required information in the log book
What should be done when the burner shuts down?
Check the water pressure on the tridicator gauge
What is the primary concern when warming up a steam boiler and its steam piping?
Preventing water hammer
Why is it essential to warm up the steam header with the boiler stop, header stop, and drain valves open?
To warm the steam header and boiler simultaneously
What should be done when the temperature of the boiler water reaches the temperature of the water in the supply main?
Open the stop valve on the boiler outlet slightly
What is the purpose of having an ample air cushion in the expansion tank during warmup?
To provide a buffer for the expanded water
What should be done when the cold boiler is at or near the system temperature?
Fully open the outlet valve
What happens when steam enters the cold steam piping during warmup?
The steam condenses heavily
What is the main benefit of warming up the boiler and steam lines simultaneously?
Preventing water hammer
What should be done when the stop valve at the boiler outlet is closed?
Close the stop valve in the return line
Why is it important to plan ahead for heating loads?
To have standby boilers warmed up prior to being required
What is the purpose of ASME VI and VII guidelines for steam boilers?
To provide general guidelines for boiler startup
What is the primary purpose of opening the boiler drum vent during the simultaneous warm-up procedure?
To release corrosive dissolved gases from the boiler water
Why is it important to maintain low fire during the initial warm-up period of a steam boiler?
To prevent thermal shock and uneven expansion
What should be done when the boiler pressure reaches 15 to 20 kPa during the warm-up procedure?
Close the drum vent valve
What is the purpose of inspecting the boiler frequently during the warm-up period?
To check for leakage and observe burner operation
When should the trap bypasses be closed during the warm-up procedure?
When the steam lines are warmed up and little condensate is blowing from the drains
What is the purpose of preparing the steam plant auxiliaries during the simultaneous warm-up procedure?
To prepare the boiler feed pump, condensate return system, and other auxiliaries
What should be done with the main disconnect switch during the simultaneous warm-up procedure?
Open it to supply power to the boiler
Why is it important to ensure the boiler control switch is in the off position during the initial stages of the warm-up procedure?
To prevent the boiler from starting accidentally
What should be done with the low point drains during the warm-up procedure?
Open them to release condensate as it forms
What is the purpose of reviewing manufacturer recommendations for burner and boiler startup during the warm-up procedure?
To follow site-specific procedures and manufacturer guidelines
This quiz covers the normal conditions encountered during the warm-up period of a boiler, including slight smoking and condensation. It's essential for operators to understand these conditions to ensure safe and efficient boiler operation. Test your knowledge of boiler warm-up and cold start conditions!
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