4BE3.5 U4 C2 Obj 5 EMH
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EASY What is the purpose of having multiple boilers in a larger steam system?

  • To ensure additional capacity is available on standby (correct)
  • To reduce thermal capacity
  • To reduce operating pressure
  • To increase the complexity of the system
  • What happens when a boiler is cut in?

  • The entire system is shut down
  • The entire system will be at low operating pressure
  • The boiler being brought on line will be at normal operating temperature
  • The boiler being brought on line will be firing from cold (correct)
  • What do steam headers in multiple boiler systems conduct?

  • Gas from the turbines to the boilers
  • Steam from the boilers to other equipment in the plant (correct)
  • Electricity from the turbines to the plant
  • Cooling water from the boilers
  • What type of header operates at 10 000 kPa?

    <p>High Pressure Header</p> Signup and view all the answers

    Why must headers and piping be properly warmed up?

    <p>To avoid thermal stress and remove condensate</p> Signup and view all the answers

    What occurs if headers and piping are not correctly warmed up?

    <p>Severe water hammer occurs during plant startup</p> Signup and view all the answers

    Who should be in control of header warm-up procedures?

    <p>A competent Power Engineer</p> Signup and view all the answers

    What is a characteristic of steam heating boilers?

    <p>Less complex than power boilers</p> Signup and view all the answers

    Why are bypass valves used in the steam piping system?

    <p>To permit finer adjustment of the warm-up rate for the steam piping</p> Signup and view all the answers

    What is the purpose of the drains located at the non-return valves and header block valves?

    <p>To drain condensate from the steam lines</p> Signup and view all the answers

    What is the primary function of the non-return valves in the steam piping system?

    <p>To prevent backflow of steam from the header</p> Signup and view all the answers

    When warming up a boiler using header steam, what should be done with the boiler's non-return valve?

    <p>Open it about 25% to regulate steam flow</p> Signup and view all the answers

    What is the purpose of the header block valve bypass valve?

    <p>To warm up the steam line to the boiler</p> Signup and view all the answers

    When is a boiler ready to be cut-in to the steam header?

    <p>When the boiler is at operating pressure and temperature</p> Signup and view all the answers

    What is the purpose of comparing the pressure on the main steam header to the pressure of the steam line to the boiler?

    <p>To determine when the boiler is ready to be cut-in</p> Signup and view all the answers

    What should be done with the non-return valve drain during warm-up?

    <p>Open it to drain condensate</p> Signup and view all the answers

    Why is it important to remove condensate from the steam lines during warm-up?

    <p>To prevent damage to the steam lines and piping</p> Signup and view all the answers

    What is the purpose of the ASME Section VII 101.3.4 procedure?

    <p>To cut in boilers to a pressurized steam header</p> Signup and view all the answers

    What happens to the non-return valve when the boiler pressure exceeds the header pressure?

    <p>It opens automatically</p> Signup and view all the answers

    What is the purpose of initially restricting the opening of the non-return valve?

    <p>To prevent sticking valves from causing flow surges and pressure upsets</p> Signup and view all the answers

    What is the first step in the method of cutting in a boiler?

    <p>Open the drain valves</p> Signup and view all the answers

    When can the Boiler 2 non-return drain valve be shut?

    <p>When it is no longer discharging condensate</p> Signup and view all the answers

    What happens to the non-return valve as Boiler 2 pressure continues to rise?

    <p>It opens slowly until it reaches the 25% limit</p> Signup and view all the answers

    What is important to be familiar with prior to cutting in additional heating boilers?

    <p>Steam heating system</p> Signup and view all the answers

    How should the boiler stop valve be opened in the absence of a non-return valve?

    <p>Slowly, when the pressures in the boiler, header, and steam line from the boiler are approximately equal</p> Signup and view all the answers

    What is the function of the drain valve in Figure 3?

    <p>To drain condensate from the steam line</p> Signup and view all the answers

    When placing a steam heating boiler on line with other boilers, what should be done first?

    <p>Start the boiler using the procedure in Objective 3</p> Signup and view all the answers

    Why is it important to open the drain valve between the stop valve at the boiler outlet and the steam main?

    <p>To drain condensate</p> Signup and view all the answers

    What is the final step in the method of cutting in a boiler?

    <p>Fully open the non-return valve</p> Signup and view all the answers

    What should be done when the pressure within the boiler is approximately the same as the pressure in the steam main?

    <p>Open the stop valve slightly</p> Signup and view all the answers

    What should be done with the drain valves at all system low points in a multiple boiler plant?

    <p>They should be left open</p> Signup and view all the answers

    What is the purpose of the double block and bleed arrangement in Figure 3(b)?

    <p>To protect workers inside boiler drums</p> Signup and view all the answers

    When warming up a boiler in a multiple boiler plant, what should be done with the boiler stop valve and the header stop valve?

    <p>They should be closed</p> Signup and view all the answers

    What is the purpose of Method One: Warming Boiler Header?

    <p>To warm up the boiler steam line</p> Signup and view all the answers

    Why is it hazardous to put a steam pipe into full service without warming it up and drying it out?

    <p>All of the above</p> Signup and view all the answers

    What should be done after the header and interconnecting piping are fully up to pressure and temperature?

    <p>Close the drains</p> Signup and view all the answers

    What is the purpose of having multiple boilers in a steam system?

    <p>To provide standby capacity during maintenance</p> Signup and view all the answers

    What is the purpose of a 10 000 kPa header in a steam plant?

    <p>For high-pressure turbine and processes</p> Signup and view all the answers

    Why is it crucial to warm up headers and piping in a steam plant?

    <p>To avoid thermal stress and water hammer</p> Signup and view all the answers

    MEDIUM Who should be in control of header warm-up procedures in a steam plant?

    <p>A competent Power Engineer</p> Signup and view all the answers

    What is a characteristic of steam heating boilers in a multiple boiler plant?

    <p>They may not have all the valves and drains of power boilers</p> Signup and view all the answers

    What happens when a boiler is cut-in to a steam header?

    <p>The boiler fires from cold, and the system is already at normal operating pressure</p> Signup and view all the answers

    What is the purpose of having multiple headers in a steam plant?

    <p>To provide multiple pressure levels for different processes</p> Signup and view all the answers

    What is the consequence of not correctly warming up and draining headers and piping?

    <p>Severe water hammer and piping damage</p> Signup and view all the answers

    What should be done with the boiler stop valve and the return stop valve when placing a steam heating boiler on line with other heating boilers that are already in service?

    <p>Both valves should be closed</p> Signup and view all the answers

    Why should the drain valve between the stop valve at the boiler outlet and the steam main be opened?

    <p>To drain condensate that accumulates above the non-return valve</p> Signup and view all the answers

    What is the purpose of opening the drain valves at all system low points in a multiple boiler plant?

    <p>To permit discharge of condensate as the steam lines warm up</p> Signup and view all the answers

    What is the purpose of the double block and bleed arrangement in Figure 3(b)?

    <p>To protect workers inside boiler drums when the connected header is energized</p> Signup and view all the answers

    What should be done with the stop valve for Boiler A when warming up the interconnecting steam piping?

    <p>It should be slightly opened</p> Signup and view all the answers

    Why is it hazardous to put a steam pipe into full service without warming it up and drying it out?

    <p>It may cause water hammer</p> Signup and view all the answers

    What should be done with the boiler stop valve and the header stop valve when warming up a boiler in a multiple boiler plant?

    <p>The boiler stop valve should be open, and the header stop valve should be closed</p> Signup and view all the answers

    When can a boiler be considered ready to be cut-in to the steam header?

    <p>When the boiler pressure is approximately the same as the pressure in the steam main</p> Signup and view all the answers

    What is the purpose of warming up the interconnecting steam piping in a multiple boiler plant?

    <p>To permit discharge of condensate as the steam lines warm up</p> Signup and view all the answers

    What should be done with the non-return valve drain during warm-up?

    <p>It should be fully opened</p> Signup and view all the answers

    What is the purpose of opening the non-return valve 25% during the initial phase of cutting in a boiler?

    <p>To prevent flow surges and pressure upsets caused by sticking valves</p> Signup and view all the answers

    What happens when the boiler pressure exceeds the header pressure in a non-return valve?

    <p>The valve opens automatically to allow steam to flow into the header</p> Signup and view all the answers

    What is the purpose of equalizing the pressure between the boiler and header stop valves using the header stop valve bypass?

    <p>To ensure a smooth transition when cutting in the boiler</p> Signup and view all the answers

    What is the correct sequence of steps when cutting in a boiler without a non-return valve?

    <p>Equalize the pressures, then open the boiler stop valve, then open the header stop valve</p> Signup and view all the answers

    What is the purpose of the drain valves located at the non-return valves and header block valves?

    <p>To remove condensate from the steam lines during warm-up</p> Signup and view all the answers

    When can the boiler be considered fully on line?

    <p>When the boiler is warmed up and the non-return valve is fully open</p> Signup and view all the answers

    What is the purpose of slowly opening the boiler stop valve in the absence of a non-return valve?

    <p>To prevent sudden pressure changes in the boiler and header</p> Signup and view all the answers

    What should be done when the pressure within the boiler is approximately the same as the pressure in the steam main?

    <p>Open the boiler stop valve slowly</p> Signup and view all the answers

    What is the primary purpose of the bypass valves located at the header block valves?

    <p>To prevent premature wear of the main steam header block valves</p> Signup and view all the answers

    When warming up a boiler using steam from the header, what should be done with the boiler's non-return valve?

    <p>Open it about 25% to allow slow warming of the steam line</p> Signup and view all the answers

    What is the significance of comparing the pressure on the main steam header to the pressure of the steam line to the boiler?

    <p>To determine if the boiler is ready to be cut-in</p> Signup and view all the answers

    Why is it important to remove condensate from the steam lines during warm-up?

    <p>To reduce the risk of water hammer</p> Signup and view all the answers

    What is the primary function of the non-return valves in the steam piping system?

    <p>To prevent backflow of steam into the boilers</p> Signup and view all the answers

    What happens to the non-return valve when the boiler pressure exceeds the header pressure?

    <p>It opens to allow steam to flow into the header</p> Signup and view all the answers

    What is the purpose of the drains located at the non-return valves and header block valves?

    <p>To remove condensate from the steam lines</p> Signup and view all the answers

    When is a boiler ready to be cut-in to the steam header?

    <p>When the boiler steam line to the header and the steam header are up to temperature and pressure</p> Signup and view all the answers

    Why is it important to open the drain valve slowly during warm-up?

    <p>To prevent water hammer</p> Signup and view all the answers

    What is the purpose of the ASME Section VII 101.3.4 procedure?

    <p>To describe the procedure for cutting in a boiler to a pressurized steam header</p> Signup and view all the answers

    What is the primary purpose of having a high-pressure header, an intermediate-pressure header, and a low-pressure header in a multiple boiler plant?

    <p>To accommodate boilers with different operating pressures.</p> Signup and view all the answers

    What is the potential consequence of not warming up headers and piping correctly in a multiple boiler plant?

    <p>Severe water hammer and piping damage.</p> Signup and view all the answers

    Who should be in control of header warm-up procedures in a multiple boiler plant?

    <p>A competent Power Engineer.</p> Signup and view all the answers

    HARD What is a characteristic of steam heating boilers in a multiple boiler plant?

    <p>They are less complex than power boilers.</p> Signup and view all the answers

    What is the primary purpose of having multiple boilers in a steam system?

    <p>To provide additional capacity on standby.</p> Signup and view all the answers

    What is the purpose of having multiple headers in a steam plant?

    <p>To accommodate boilers with different operating pressures.</p> Signup and view all the answers

    What happens when a boiler is cut-in to a steam header?

    <p>The boiler begins firing from cold.</p> Signup and view all the answers

    Why is it crucial to warm up headers and piping in a steam plant?

    <p>To avoid severe water hammer and piping damage.</p> Signup and view all the answers

    What is the primary purpose of initially restricting the opening of the non-return valve?

    <p>To prevent flow surges and pressure upsets caused by sticking valves</p> Signup and view all the answers

    What happens when the boiler pressure exceeds the header pressure?

    <p>The non-return valve opens automatically</p> Signup and view all the answers

    What is the purpose of opening the bypass on the header stop valve?

    <p>To equalize the pressure between the boiler and header</p> Signup and view all the answers

    When can the boiler non-return valve be fully opened?

    <p>When the boiler steam line is at temperature and pressure</p> Signup and view all the answers

    In the absence of a non-return valve, how should the boiler stop valve be opened?

    <p>Slowly, to equalize pressures</p> Signup and view all the answers

    What is the purpose of the drain valves located at the non-return valves and header block valves?

    <p>To remove condensate from the steam lines</p> Signup and view all the answers

    What happens when the non-return valve sticks in the closed position?

    <p>It opens suddenly, causing flow surges and pressure upsets</p> Signup and view all the answers

    What is the final step in the method of cutting in a boiler?

    <p>Opening the non-return valve fully</p> Signup and view all the answers

    What is the primary purpose of using bypass valves in the steam piping system?

    <p>To warm up the steam lines to the boilers</p> Signup and view all the answers

    What is the significance of comparing the pressure on the main steam header to the pressure of the steam line to the boiler?

    <p>To determine if the boiler is ready to be cut-in</p> Signup and view all the answers

    What is the purpose of restricting the initial opening of the non-return valve?

    <p>To prevent wire drawing of the main steam header block valves</p> Signup and view all the answers

    What is the consequence of not correctly warming up and draining headers and piping?

    <p>Wire drawing of the main steam header block valves may occur</p> Signup and view all the answers

    When can a boiler be cut-in to the steam header?

    <p>When the header and interconnecting piping are up to temperature and pressure</p> Signup and view all the answers

    What is the purpose of the drain valves located at the non-return valves and header block valves?

    <p>To drain condensate from the steam lines</p> Signup and view all the answers

    What is the purpose of opening the drain valves at all system low points in a multiple boiler plant?

    <p>To drain condensate from the steam lines</p> Signup and view all the answers

    What is the purpose of the header block valve bypass valve?

    <p>To warm up the steam lines to the boilers</p> Signup and view all the answers

    Why is it crucial to warm up headers and piping in a steam plant?

    <p>To prevent wire drawing of the main steam header block valves</p> Signup and view all the answers

    What is the purpose of Method One: Warming Boiler Header?

    <p>To warm up the steam lines to the boilers</p> Signup and view all the answers

    What is the primary purpose of warming up a steam header in a multiple boiler plant?

    <p>To prevent water hammer</p> Signup and view all the answers

    When warming up a boiler in a multiple boiler plant, what should be done with the boiler stop valve and the header stop valve?

    <p>They should be closed</p> Signup and view all the answers

    What is the purpose of the drain valve between the stop valve at the boiler outlet and the steam main?

    <p>To drain condensate from the steam main</p> Signup and view all the answers

    When should the boiler stop valve be fully opened?

    <p>When the pressure within the boiler is approximately the same as the pressure in the steam main</p> Signup and view all the answers

    What is the purpose of the double block and bleed arrangement in Figure 3(b)?

    <p>To protect workers inside the boiler drums</p> Signup and view all the answers

    Why is it important to open the drain valves at all system low points in a multiple boiler plant?

    <p>To prevent water hammer</p> Signup and view all the answers

    What should be done when the pressure within the boiler is approximately the same as the pressure in the steam main?

    <p>The boiler stop valve should be fully opened</p> Signup and view all the answers

    What is the purpose of Method One: Warming Boiler Header?

    <p>To warm up the interconnecting steam piping</p> Signup and view all the answers

    Why is it hazardous to put a steam pipe into full service without warming it up and drying it out?

    <p>It may cause water hammer</p> Signup and view all the answers

    What should be done after the header and interconnecting piping are fully up to pressure and temperature?

    <p>The drain valves should be closed</p> Signup and view all the answers

    Study Notes

    Multiple Boiler Systems

    • Multiple boilers are used to provide additional thermal capacity and ensure standby capacity is available when needed.
    • Each boiler can be brought online from a cold start, firing from cold while the entire system is hot and at normal operating pressure.

    Steam Headers

    • Steam headers conduct steam from boilers to other equipment in the plant.
    • Large and complex high-pressure steam plants can have multiple headers, identified by their operating pressures.
    • Examples of headers include:
      • High-Pressure Header (10 000 kPa) for high-pressure turbines and processes.
      • Intermediate Pressure Header (2500 kPa) for intermediate-pressure turbines and processes.
      • Low-Pressure Header (100 kPa) for steam heating and auxiliary equipment.

    Header Warm-up Procedures

    • Headers and piping must be properly warmed up to avoid thermal stress and remove condensate as it forms.
    • Incorrect warm-up procedures can lead to severe water hammer during plant startup.
    • In multiple boiler or multiple header plants, header warm-up procedures can be complex and must be performed under the control of a competent Power Engineer.

    Cutting in Boilers

    • Cutting in a boiler involves bringing it online and connecting it to the steam header.
    • There are different warm-up procedures for boilers, depending on whether all boilers have been shut down or if some boilers are already online.
    • Common procedures for warming up boilers include:
      • Opening drain valves at all system low points to discharge condensate as steam lines warm up.
      • Warming up the steam line to the header using steam from the boiler or the header.
      • Using bypass valves to warm up the steam line to the boiler.
      • Ensuring the boiler and header are at the same pressure and temperature before cutting in the boiler.

    Specific Procedures for Cutting in Boilers

    • Method One: Warming Boiler Header
      • Open drain on non-return valve.
      • Slightly open header valve to allow steam to flow from the header into the boiler steam line.
      • Open header valve fully when the pressure has equalized between the steam header and boiler steam line.
    • Method Two: Warming Boiler Header
      • Open drain on non-return valve.
      • Open header block valve drain.
      • Open non-return valve about 25%.
      • Slowly open header block valve bypass valve to warm up the steam line to the boiler.
      • Permit drains to blow until the header and interconnecting piping are fully up to pressure and temperature.

    Cutting in Boilers with Non-Return Valves

    • Cut-in the boiler when the boiler steam line to the header and the steam header are up to temperature, and their pressures are equal.
    • Method One: Cutting in a Boiler
      • Open non-return valve about 25% when the boiler pressure is still a few kPa below the header pressure.
      • Backing off on the stem of the non-return valve permits it to automatically open as the boiler pressure exceeds the header pressure.
      • Open non-return valve fully when the boiler is supplying steam and there are no unusual conditions.
    • Method Two: Cutting in a Boiler
      • Open drain valves and non-return valve 25%.
      • Warm up the boiler steam line using the header steam.
      • Open bypass on header stop valve.
      • Cut in the boiler to the header when the steam line is at temperature and pressure.
      • Close drain valves and open header stop valve fully.

    Cutting in Boilers without Non-Return Valves

    • In this situation, the boiler does not have non-return valves, but rather conventional OS&Y rising stem valves.
    • The boiler stop valve should be opened slowly when the pressures in the boiler, header, and steam line from the boiler are approximately equal.
    • Equalize the pressure between the boiler and header stop valves using the header stop valve bypass.
    • When the header pressure equals the boiler steam line pressure, the header stop valve can be slowly opened fully and its drain shut.

    Multiple Boiler Systems

    • Multiple boilers are used to provide additional thermal capacity and ensure standby capacity is available when needed.
    • Each boiler can be brought online from a cold start, firing from cold while the entire system is hot and at normal operating pressure.

    Steam Headers

    • Steam headers conduct steam from boilers to other equipment in the plant.
    • Large and complex high-pressure steam plants can have multiple headers, identified by their operating pressures.
    • Examples of headers include:
      • High-Pressure Header (10 000 kPa) for high-pressure turbines and processes.
      • Intermediate Pressure Header (2500 kPa) for intermediate-pressure turbines and processes.
      • Low-Pressure Header (100 kPa) for steam heating and auxiliary equipment.

    Header Warm-up Procedures

    • Headers and piping must be properly warmed up to avoid thermal stress and remove condensate as it forms.
    • Incorrect warm-up procedures can lead to severe water hammer during plant startup.
    • In multiple boiler or multiple header plants, header warm-up procedures can be complex and must be performed under the control of a competent Power Engineer.

    Cutting in Boilers

    • Cutting in a boiler involves bringing it online and connecting it to the steam header.
    • There are different warm-up procedures for boilers, depending on whether all boilers have been shut down or if some boilers are already online.
    • Common procedures for warming up boilers include:
      • Opening drain valves at all system low points to discharge condensate as steam lines warm up.
      • Warming up the steam line to the header using steam from the boiler or the header.
      • Using bypass valves to warm up the steam line to the boiler.
      • Ensuring the boiler and header are at the same pressure and temperature before cutting in the boiler.

    Specific Procedures for Cutting in Boilers

    • Method One: Warming Boiler Header
      • Open drain on non-return valve.
      • Slightly open header valve to allow steam to flow from the header into the boiler steam line.
      • Open header valve fully when the pressure has equalized between the steam header and boiler steam line.
    • Method Two: Warming Boiler Header
      • Open drain on non-return valve.
      • Open header block valve drain.
      • Open non-return valve about 25%.
      • Slowly open header block valve bypass valve to warm up the steam line to the boiler.
      • Permit drains to blow until the header and interconnecting piping are fully up to pressure and temperature.

    Cutting in Boilers with Non-Return Valves

    • Cut-in the boiler when the boiler steam line to the header and the steam header are up to temperature, and their pressures are equal.
    • Method One: Cutting in a Boiler
      • Open non-return valve about 25% when the boiler pressure is still a few kPa below the header pressure.
      • Backing off on the stem of the non-return valve permits it to automatically open as the boiler pressure exceeds the header pressure.
      • Open non-return valve fully when the boiler is supplying steam and there are no unusual conditions.
    • Method Two: Cutting in a Boiler
      • Open drain valves and non-return valve 25%.
      • Warm up the boiler steam line using the header steam.
      • Open bypass on header stop valve.
      • Cut in the boiler to the header when the steam line is at temperature and pressure.
      • Close drain valves and open header stop valve fully.

    Cutting in Boilers without Non-Return Valves

    • In this situation, the boiler does not have non-return valves, but rather conventional OS&Y rising stem valves.
    • The boiler stop valve should be opened slowly when the pressures in the boiler, header, and steam line from the boiler are approximately equal.
    • Equalize the pressure between the boiler and header stop valves using the header stop valve bypass.
    • When the header pressure equals the boiler steam line pressure, the header stop valve can be slowly opened fully and its drain shut.

    Multiple Boiler Systems

    • Multiple boilers are used to provide additional thermal capacity and ensure standby capacity is available when needed.
    • Each boiler can be brought online from a cold start, firing from cold while the entire system is hot and at normal operating pressure.

    Steam Headers

    • Steam headers conduct steam from boilers to other equipment in the plant.
    • Large and complex high-pressure steam plants can have multiple headers, identified by their operating pressures.
    • Examples of headers include:
      • High-Pressure Header (10 000 kPa) for high-pressure turbines and processes.
      • Intermediate Pressure Header (2500 kPa) for intermediate-pressure turbines and processes.
      • Low-Pressure Header (100 kPa) for steam heating and auxiliary equipment.

    Header Warm-up Procedures

    • Headers and piping must be properly warmed up to avoid thermal stress and remove condensate as it forms.
    • Incorrect warm-up procedures can lead to severe water hammer during plant startup.
    • In multiple boiler or multiple header plants, header warm-up procedures can be complex and must be performed under the control of a competent Power Engineer.

    Cutting in Boilers

    • Cutting in a boiler involves bringing it online and connecting it to the steam header.
    • There are different warm-up procedures for boilers, depending on whether all boilers have been shut down or if some boilers are already online.
    • Common procedures for warming up boilers include:
      • Opening drain valves at all system low points to discharge condensate as steam lines warm up.
      • Warming up the steam line to the header using steam from the boiler or the header.
      • Using bypass valves to warm up the steam line to the boiler.
      • Ensuring the boiler and header are at the same pressure and temperature before cutting in the boiler.

    Specific Procedures for Cutting in Boilers

    • Method One: Warming Boiler Header
      • Open drain on non-return valve.
      • Slightly open header valve to allow steam to flow from the header into the boiler steam line.
      • Open header valve fully when the pressure has equalized between the steam header and boiler steam line.
    • Method Two: Warming Boiler Header
      • Open drain on non-return valve.
      • Open header block valve drain.
      • Open non-return valve about 25%.
      • Slowly open header block valve bypass valve to warm up the steam line to the boiler.
      • Permit drains to blow until the header and interconnecting piping are fully up to pressure and temperature.

    Cutting in Boilers with Non-Return Valves

    • Cut-in the boiler when the boiler steam line to the header and the steam header are up to temperature, and their pressures are equal.
    • Method One: Cutting in a Boiler
      • Open non-return valve about 25% when the boiler pressure is still a few kPa below the header pressure.
      • Backing off on the stem of the non-return valve permits it to automatically open as the boiler pressure exceeds the header pressure.
      • Open non-return valve fully when the boiler is supplying steam and there are no unusual conditions.
    • Method Two: Cutting in a Boiler
      • Open drain valves and non-return valve 25%.
      • Warm up the boiler steam line using the header steam.
      • Open bypass on header stop valve.
      • Cut in the boiler to the header when the steam line is at temperature and pressure.
      • Close drain valves and open header stop valve fully.

    Cutting in Boilers without Non-Return Valves

    • In this situation, the boiler does not have non-return valves, but rather conventional OS&Y rising stem valves.
    • The boiler stop valve should be opened slowly when the pressures in the boiler, header, and steam line from the boiler are approximately equal.
    • Equalize the pressure between the boiler and header stop valves using the header stop valve bypass.
    • When the header pressure equals the boiler steam line pressure, the header stop valve can be slowly opened fully and its drain shut.

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    Description

    This quiz assesses understanding of non-return valves and their operation in boiler systems, including pressure control and flow management.

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