Block 2 - Commission Fuel Train Components & ICI Burners Flashcards
What is the responsibility of a technician when commissioning an appliance?
You become responsible for any appliance you commission regardless of whether you pulled the permits or not.
Before commissioning an appliance not installed by your company, what should you verify?
Check if all appropriate permits are in order by contacting the safety officer.
What information does a gas safety officer need for commissioning?
- Customer name
- Company site name and address
- Manufacturer and type of appliance
What is the CRN# used for?
It will give you a complete history of the boiler, from the manufacturer to the present.
What types of permits are needed for commissioning?
- Piping installation permit
- Appliance installation permit
- Appliance product approval permit
- Boiler installation permit
What should be checked during a site visit prior to commissioning?
- Gas piping size and pressure
- CSA approval for the appliance
- Fuel train compliance
- Flu venting correctness
- Combustion air requirements
- Gas meter size
- Electrical completeness
- Feed water and boiler piping
- Air dampers and gas linkages
- Gas pressure adequacy
What should be done with all gas firing valves before starting checks?
Close all gas firing valves.
What does PTFI stand for?
Pilot Trial for Ignition.
What is the purpose of a pilot turn down test?
To ensure that the smallest pilot flame will hold in the flame relay and ignite the main flame safely.
What is the turndown ratio in relation to firing rate?
It indicates the flexibility of the burner to satisfy heating demands without cycling.
What is the initial airflow setting based on?
The calculated combustion air requirements.
What is excess air in combustion?
The amount of air supplied beyond the stoichiometric requirements for complete combustion.
True or False: A zero governor system allows for more than two adjustments.
False.
What adjustments are made for high fire settings?
Adjust the high fire air/gas ratio by turning the air valve and adjusting the limiting orifice gas valve.
What is the purpose of an impulse line in a combustion system?
To correct the regulator action and compensate for variable combustion chamber pressure.
Fill in the blank: The _____ needs to be checked and confirmed during the commissioning process.
combustion analysis
What is the significance of checking gas inlet pressures?
To ensure proper function of high and low gas pressure switches.
What should be done if clocking is not possible due to other appliances firing?
An orifice plate may need to be installed.
What is the role of the line pressure regulator?
To set the initial pressure settings for a burner based on manufacturer specifications.
What should be monitored during airflow adjustments?
Combustion parameters such as flame appearance, stability, and color.
What is the recommended excess air percentage for adjustments?
Around 3% to 5% excess air.
What is the effect of combustion chamber pressure fluctuations?
It can upset control of the system.
What is the minimum inlet pressure required for a regulator sized to take a 3 iwc pressure drop at full fre conditions?
31 iwc or more
This is calculated by adding the pressure drop (3 iwc) to the desired outlet pressure (28 iwc)
What is the desired safety factor added to the required supply pressure?
2 in
This is added to ensure a margin of safety in pressure supply
What is the required supply pressure if the regulator is sized for a 10 in wc drop?
40 in
This is calculated by adding the pressure drop (10 in) to the desired outlet pressure (28 in) and the safety factor (2 in)
What should be checked when commissioning an appliance with a fan-assisted burner?
Manufacturer’s installation instructions
It is crucial to follow specific guidelines to ensure safety and proper operation
True or False: If the draft is too low, you should remove weight from the damper chain.
False
Adding weight to the damper chain will choke dilution air and increase the draft
What should be done if the draft is too high?
Remove weight from the damper chain
This adjustment allows more dilution air in and decreases the draft
What is the purpose of the FGR inlet box?
Pulls fuel gas from the sack and delivers it to the combustion air fan inlet
This is essential for the proper operation of a FGR system
What is the function of the FGR flow control damper?
Regulates the quantity of fuel gas to the FGR inlet box
It is designed for high-temperature operation and is driven by a damper actuator
Fill in the blank: The ductwork must be installed to be ______ with high temperature gasketing at duct joints.
gas tight
Ensuring gas-tight ductwork prevents leaks and maintains system efficiency
What should be done if the temperature in the ductwork exceeds a maximum set point?
Shut down the burner
This prevents damage to FGR components due to backflow from the boiler
What is a crucial step during the FGR system start-up procedure?
Review the burner instruction manual
This ensures that all safety checks and standard procedures are followed
What happens if the burner is operated without the FGR blower in operation?
Overheating and possible damage to the FGR manifold assembly
This can compromise the safety and functionality of the system
What is the recommended setting for the stack temperature switch?
A few degrees below the normal low fire sack temperature
This ensures the system operates safely and effectively
What is the relationship between FGR rate and combustion air flow?
Increasing the FGR rate will lower the combustion air flow
This is indicated by lower sack O2 levels
What is the effect of too much FGR on combustion stability?
Can cause instability and combustibles (CO or smoke)
It is essential to fine-tune the FGR damper position for optimal performance
What should be done to ensure the burner can ramp from low fire to high fire and back?
Make adjustments at each load point until proper emissions and performance are achieved
Each adjustment should be monitored for stability and efficiency
What are burner pulsations also known as?
Combustion instabilities
These can affect the efficiency and safety of the burner operation
What are burner pulsations?
Burner pulsations, also known as combustion instabilities, are fluctuations in flame intensity caused by various factors.
What can cause fuel-air mixture imbalance?
An improper balance of fuel to air can lead to incomplete combustion and fluctuations in flame intensity.
Name two factors that affect flame stability.
- Flame shape
- Flame size
- Flame position within the combustion chamber
How does combustion chamber design contribute to burner pulsations?
Poor combustion chamber design can create conditions conducive to pulsations due to inadequate mixing of fuel and air or improper geometry.
What impact does fuel quality have on combustion stability?
Variations in fuel quality, including changes in composition or impurities, can impact combustion stability and contribute to pulsations.
List three issues related to burner design and operation that can cause pulsations.
- Improper nozzle sizing
- Clogging
- Malfunctioning controls
What operating conditions can affect combustion dynamics?
- Load fluctuations
- Ambient temperature
- Pressure variations
How can mechanical vibrations influence combustion stability?
External mechanical vibrations from nearby equipment or structural resonance can influence combustion stability and cause pulsations.
What ignition problems can lead to burner pulsations?
Inconsistent or delayed ignition can disrupt the combustion process and result in pulsations.
Fill in the blank: Certain combustion instability modes, such as ________, can occur under specific conditions and cause pulsations.
[thermo-acoustic oscillations or vortex shedding]
What role does system feedback play in combustion instabilities?
Feedback mechanisms within the combustion system, such as acoustic resonance or pressure fluctuations, can amplify combustion instabilities and lead to pulsations.
What maintenance issues can contribute to burner pulsations over time?
Lack of regular maintenance, including cleaning of burner components and calibration of controls.
What should you check to ensure a steady fuel supply to the burner?
Ensure that there’s a steady and adequate supply of fuel to the burner.
Why is it important to inspect combustion air supply?
Inadequate air supply can lead to incomplete combustion and pulsations.
What should be examined in the burner assembly to prevent pulsations?
Examine the burner assembly for any signs of damage, clogging, or misalignment.
What role do burner controls play in burner operation?
Malfunctioning controls can cause erratic burner operation.
What should be monitored to identify the source of pulsations?
Monitor combustion parameters such as flame stability, fuel-air ratio, and combustion efficiency.
What can be done if the fuel nozzle is clogged or worn?
Clean or replace the nozzle as needed.
How can mechanical vibrations from nearby equipment affect the burner operation?
They can influence combustion stability and contribute to pulsations.
What should you do if there are changes in operating conditions?
Consider any variations in fuel quality or load demand that may contribute to burner pulsations.
What is the purpose of consulting the manufacturer’s guidelines?
To refer to specific troubleshooting steps and recommended maintenance procedures.
What is a recommended practice during test runs to diagnose pulsations?
Conduct test runs with gradual adjustments to burner settings while monitoring for changes in pulsation behavior.
What is the purpose of the procedure developed in B149.3 Annex A?
To help ensure safe start-up of high input gas-fired equipment
The procedure acknowledges variation in equipment types and controls.
What should be confirmed regarding the valve train before start-up?
The valve train must be code compliant for the burner input of the appliance
More information can be found in B149.3 Annex B – Valve Diagrams.
What does ASME CSD1 recommend regarding the installation of a strainer?
The installation of a strainer before the horizontal components in the gas train
It is a recommendation, not a requirement.
What is the requirement for testing the valve seats?
The valve shall be tested to ensure gas-tightness of the valve seats when in the closed position.
What should be checked with the Appliance shutoff valve?
There should be no pressure downstream when the Appliance shutoff valve is closed.
What should be monitored when checking tightness of closure for the SSOVs?
Monitor pressure upstream and downstream of the SSOVs as you cycle the individual valves.
What type of valve is recommended for test firing?
A test firing valve of the quarter-turn type, certified to CGA 3.11, CGA 3.16, or ANSI Z21.15/CSA 9.1.
What is the maximum allowable closing time for electro-hydraulic SSOVs?
They are required to close within 1 second.
What is the purpose of a Valve Proving System (VPS)?
To cycle the valves and monitor pressures automatically at the beginning of each cycle.
What is the difference between Passive VPS and Active VPS?
Passive VPS is a static system; Active VPS is a separate system with advanced instrumentation.
What does B149.3 clause 4.4 state about pressure regulators?
The pressure regulator shall maintain an outlet pressure within 10% of the set pressure during burner operation.
What is required when the inlet supply pressure to the pressure regulator exceeds 0.5 psig?
The pressure regulator shall be a lock-up (positive shut-off) pressure regulator.
What is the function of gas pressure switches?
To monitor the functionality of the regulator and shut down the burner if unsafe conditions arise.
Fill in the blank: A high gas pressure safety device shall initiate shut-off of the supply of gas when the gas pressure exceeds _______.
125% of the normal operating pressure at the maximum firing rate.
What must be checked regarding the operation of the Proof of Closure switch?
Confirm the operation of the Proof of Closure switch if equipped.
True or False: The valve seat ‘bubble’ test is an annual maintenance requirement for most fuel-fired equipment standards.
True.
What should be confirmed when adjusting gas pressure regulators?
Confirm that the amount of droop or boost does not exceed what is allowed.
What is the purpose of Overpressure Protection (OPP)?
To protect the system from excessive pressure situations.
What conditions might require a low gas pressure safety device?
If the pressure at the point of connection drops below 50% of the lowest normal operating pressure.
What should be monitored when installing a manometer or pressure gauge?
Monitor the pressure between the SSOVs for any increase that indicates a leaking first valve.
What is the consequence of not ensuring tight shut-off of fuel valves?
Foreign material may prevent tight closure, leading to leakage and potential hazards.
What is the function of the low gas pressure safety device?
Bypassed into the combustion safety control until the burner has started.
This is a precaution to ensure safety during the ignition process.
When is the lowest normal operating pressure observed in a gas burner?
While the burner is at high fire and the regulator is experiencing its maximum allowable droop.
What do modern unified valves combine?
- Pressure regulation
- Valve closing
- Variable flow rate
- Pressure switches
Consult manufacturers’ documentation for specific adjustments.
What is the purpose of the Proof of Closure option?
To ensure that the valve is fully closed when required.
How should the position of the flow control valve be adjusted?
For the different firing rates while setting combustion and using a combustion analyzer.
What does the fuel cam control in a burner?
The position of the input flow control valve.
According to B149.3 Clause 8.2.2, what features must an automatic input flow control valve have?
- Capable of adjustment for sufficient gas
- Means for preventing accidental change in settings
- Accessible for service and adjustment
What should be done when making fuel adjustments?
Set and lock the high fire and low fire stops on the overtravel linkage.
What does the FARC system stand for?
Fuel Air Ratio Control.
What is a characteristic of a parallel position system in FARC?
Individual actuators facilitate precise adjustment to a single valve or damper position.
What is the role of instrumentation in sophisticated systems?
To determine real-time flow rate to the burner for adjustment and calibration.
How are oil burner valve trains arranged compared to gas fuel valve trains?
They are arranged similarly with some exceptions.
What is an ‘oil block’ in oil burner valve trains?
Several oil valve train components combined into a single device, with each function still requiring separate adjustments.
What components should be included in an oil burner system?
- Strainer
- Filter
- Water separator
This is essential for maintaining fuel quality.
Where can the oil pump be located in an oil burner system?
On the appliance or further upstream in the piping.
What affects the pressure to the oil nozzle in an oil burner?
How the oil is atomized (e.g., air atomized, pressure atomized, steam atomized).
How do pressure atomized nozzles maintain nozzle pressure?
By adjusting the bypass regulator.
What are SSOVs in a fuel system?
Normally closed solenoid valves that are piped in series and wired in parallel as a double block.
What is the purpose of metering valves in an oil burner?
To provide precise control of the fuel oil.
What is a metering sem?
A component that can be lowered or raised to expose more or less of the cut V-groove.
What challenges arise in a dual gas fuel system?
Some parts of the valve train will be independent to each fuel, while others will be common.
What is the adjustment priority in linkage systems for combustion settings?
Adjust the air damper linkage for the primary fuel first, then the secondary fuel.
How is each fuel curve adjusted in appliances with parallel position systems?
Independently for each fuel and air trimmed independently.
