he fire heater requires inspection and maintenance

The fire heater requires inspection and maintenance. At a minimum, the following checks should be completed:

- Examine the fire heater coils and furnace for any signs of corrosion, cracking, or other damage. Clean if needed.

- Check the fuel system including pipes, valves, pumps, and filters. Ensure there are no leaks or clogged components.

- Inspect the combustion air blower and fan for smooth operation and replace air filters.

- Verify proper operation of safety controls like temperature and pressure switches, flame scanners, etc.

- Test ignition system and pilot light. Replace any igniters or thermocouples as needed.

- Inspect exhaust piping and stack for any blockages or corrosion issues.

- Confirm proper airflow by checking dampers and ductwork. Adjust as needed.

Please let me know if you need any clarification or have additional requests regarding inspection and maintenance of the fire heater.

1. Fire Heater

2. Device Fired Heater Heat Exchanger Function Elevates the temperature of process fluids directly through fuel combustion. Facilitates heat transfer between two fluids without mixing them. Working Principle Directly heats the tubes containing the process fluid using combustion gases. Allows two separate fluids at different temperatures to transfer heat from the hotter to the cooler fluid. Combustion Contains an internal combustion chamber for burning fuel. Does not involve combustion; depends on external heat sources. Temperature Capable of reaching extremely high temperatures, often required for chemical processes. The temperature range is determined by the fluids used and their heat sources. Structure Composed of burners, firebox, radiant section, convection section, and stack. Made up of tubes, shell, and sometimes fins or plates to enhance heat transfer. Fluids Used Generally, involves gases and liquids specific to the refining or chemical process. Can handle any combination of gases, liquids, and even phase changes (like condensation or boiling). Usage Predominantly used in refineries and petrochemical plants for processing fuels and chemicals. Employed in various industries for cooling, heating, or recovering heat from processes.

3. Process Detailed Explanation Role of Fired Heater Distillation This process involves heating liquids until they turn into vapor. The vapor is then condensed back into liquid form and collected. The goal is to separate the original liquid into different components based on their boiling points. Fired heaters are used to heat the oil to the necessary temperature where it can be separated into its constituent parts. Cracking Cracking involves using heat to break down large hydrocarbon molecules into smaller ones. This process is often used in the petroleum industry to convert long-chain hydrocarbons into shorter ones. Fired heaters provide the high temperatures needed to break the large hydrocarbon molecules apart. Reforming Reforming is a process used in the petroleum industry to improve the quality of gasoline. It involves changing the structure of hydrocarbon molecules using heat and a catalyst. Fired heaters supply the heat necessary to facilitate the structural changes in the hydrocarbon molecules. Treating Treating is a process used to clean oil by removing impurities. This is often done using chemicals or other treatment methods. Fired heaters are sometimes used to heat the oil during the treatment process, which can help in the removal of impurities. Catalytic Catalytic processes involve using a catalyst to speed up chemical reactions. This is often used in the petroleum and chemical industries to increase the efficiency of various processes. Fired heaters are used to bring the process to the necessary temperature for the catalytic reactions to occur.

4. Process Detailed Explanation Role of Fired Heater Sweetening Sweetening is a process used to remove sulfur compounds from sour gas, making it ‘sweet’. This is important because sulfur compounds can be corrosive and harmful to the environment. Fired heaters may be used to warm the gases to the necessary temperature for the chemical reactions involved in sweetening to occur. Dehydration Dehydration involves removing water from gas to prevent issues in pipelines, such as corrosion or the formation of hydrates. Fired heaters are sometimes used to heat the gas, which can help in the removal of moisture. NGL Extraction NGL (Natural Gas Liquids) extraction involves separating valuable liquids like propane and butane from natural gas. Fired heaters may be used to warm up the gases, which can help in the separation of the liquids. Steam Reforming for Ammonia Steam reforming is a process used to produce ammonia. It involves reacting natural gas with steam at high temperatures. Fired heaters provide the intense heat necessary for the steam reforming reaction to occur. Steam Cracking for Olefins Steam cracking is a process used to produce olefins (small molecules). It involves using steam to break down large hydrocarbon molecules. Fired heaters provide the high temperatures necessary to break down the large hydrocarbon molecules into smaller olefins.

5. Industry Application of Fired Heaters Refineries - Used to heat materials during refining processes. - Transform raw materials into products such as gasoline, diesel, etc - The heated fluids like oil are utilized in different parts of the plant for various needs, including steam generation. Petrochemical Sector - Employed to heat fluids to the required temperatures for processing. - Transform crude oil, residues, and gas oils into transportation fuels and other chemical products. Gas Processing Facilities - Serve to provide direct or indirect heating for process requirements. - Maintain high temperatures and pressures for gas processing applications. Ammonia and Olefin Plants - Utilized to elevate the temperature of process fluids in production. - Provide heat energy for chemical reactions that are vital in the production of ammonia and olefins. Fertilizer Manufacturing - Employed to heat fluids to the necessary temperatures for production processes. - Ensure the efficient operation of processes that require high temperatures, such as the synthesis of various fertilizers.

6. production of chemicals ammonia and olefins Utilized to elevate the temperature of process fluids in production. In industrial settings, many production processes require that fluids (which could be raw hydrocarbons, intermediates, or other chemical mixtures) be heated to specific temperatures for efficient processing. Elevated temperatures can increase reaction rates, improve material flow, or enable certain chemical reactions to occur. Fired heaters are used to directly heat these process fluids. They do this by burning a fuel (such as natural gas, oil, or process by-products) to generate heat, which is then transferred to the process fluid within coils or tubes. By controlling the temperature of the process fluid, fired heaters ensure that the desired chemical and physical changes take place within the system at the right efficiency and rate. Provide heat energy for chemical reactions that are vital in the production of ammonia and olefins. The production of chemicals like ammonia and olefins involves endothermic reactions, which require the absorption of heat. For instance: Ammonia Production: The Haber-Bosch process combines nitrogen and hydrogen gases under high temperatures (400-500°C) and pressures to produce ammonia. Fired heaters supply the necessary heat to reach and maintain these temperatures for the reaction to proceed efficiently. Olefin Production: Olefins, such as ethylene and propylene, are typically produced through processes like steam cracking, where long-chain hydrocarbons are heated to high temperatures, causing the molecular bonds to break and form smaller, olefinic molecules. Fired heaters provide the heat required for this thermal cracking process.

7. Part Functionality Potential Reliability Peep Door Allows visual inspection of the interior of the heater, including the flame. High reliability if properly maintained and used. However, frequent opening can cause heat loss and inefficiency. Louvers Regulate air flow into the heater for combustion. Generally reliable, but can be subject to wear and require calibration to ensure proper air flow. Pilot Ignites the main burner flame and ensures continuous operation. High reliability, though it must be monitored to ensure it remains lit and functional. Burner Mixes fuel with air and allows for combustion to take place. Reliability varies with design and maintenance; precision components can be sensitive to conditions. Refractory Insulates the heater’s walls, retains heat, and protects structural components. Subject to wear from thermal cycling and can crack or degrade, affecting heater efficiency and safety.

8. Part Functionality Potential Reliability Radiation Zone Area where the majority of heat transfer occurs via radiation. High reliability if the refractory is intact, but can be affected by high temperatures and flame impingement. Shock/Shield Section Protects downstream tubes from direct flame radiation and thermal shock. Reliable when designed correctly, but can be compromised by excessive heat or mechanical stress. Convection Zone Area where heat is transferred mainly through convection. Reliability depends on the cleanliness and integrity of heat exchange surfaces and proper gas flow. Breeching/Transition Duct Channels combustion gases from the heater to the stack or next heating stage. Usually reliable, but subject to corrosion and wear from the acidic condensates and high temperatures. Damper Adjusts the draft or flow of flue gases through the heater. If properly maintained, dampers are reliable, but they can seize or degrade if not operated regularly. Stack Discharges combustion gases to the atmosphere at a safe height. High reliability; however, structural integrity can be compromised by corrosion and external conditions.

9. Radiant Shape Function Advantages Vertical Tubes are arranged vertically, allowing for natural convection to assist with heat transfer. Simplifies structural design. Promotes natural convection. Easier tube inspection and maintenance. Cabin (Single) A single box-like enclosure with tubes arranged on the walls, absorbing heat from a central flame. Compact design. Good for small to medium-sized applications. Relatively even heat distribution. Cabin (Twin) Similar to single cabin, but with two side-by-side enclosures sharing a common wall. Higher capacity than single cabin. Can handle larger process throughput. Efficient use of space with shared structures. Central A central column of radiant tubes, often with burners placed around the periphery. Centralized heat source. Can offer good heat flux uniformity. Suitable for cylindrical heater designs. Wicket “Arbor” Tubes are arranged in a wicket or arch shape, resembling a garden arbor. Can accommodate large volume expansions. Good for high-temperature applications. Reduced stress on tube connections. Inverted An upside-down arrangement, where the tubes are supported from above. Reduces the accumulation of debris on tube surfaces. Helpful in dirty service applications. Eases bottom access for maintenance. Helical Coils are arranged in a helical or spiral configuration. Maximizes surface area in a given volume. Can enhance heat transfer due to centrifugal forces on the fluid. Often used for high-pressure applications.

10. Vertical tube cylindrical heater

11. Convection section .

12. Radiant section.

13. Horizontal box type [ single shell/ twin shell

14. Arbor or wicket type heater

15. Inverted wicket type

16. Helical coil heater

17. Draft Type Mechanism Design Advantages Natural Draft Relies on natural convection Simpler design with fewer moving parts, Lower operating costs as no fans are required, Generally lower maintenance Forced Draft Uses a fan (F.D fan) to push air into the burner More control over air flow, Can handle larger system capacities, Less influenced by external weather conditions Induced Draft Uses a fan (I.D fan) to pull flue gases out Better control of combustion due to a maintained negative pressure, Can reduce the risk of flue gas leakage Balanced Draft Uses both F.D and I.D fans Combines the advantages of forced and induced drafts, Precise control over air flow and system pressure

18. Tube Type Function Advantages Bare Tubes Serve as the most basic heat exchange surface; direct contact with the combustion gases allows for heat transfer. Simplicity in design and maintenance. Lower cost compared to enhanced surfaces. Easier to clean. Finned Tubes Increase the external surface area for heat transfer without significantly increasing the heater’s footprint. Enhanced heat transfer efficiency due to increased surface area. Can achieve higher heat transfer with a smaller size compared to bare tubes. Suitable for applications with space constraints. Stud Tubes Typically used for high-viscosity fluids; studs provide additional surface area for heat transfer. Good for heavy fouling services. Higher heat transfer area per unit length compared to bare tubes. Can handle viscous fluids better than other designs. Segmental Tubes Used in very high-temperature applications; segments or fins are attached in a segmented pattern. Allow for thermal expansion without causing stress on the tube walls. High heat transfer efficiency at very high temperatures. Can be used in applications with particulate-laden gases.

19. Bare tubes Studded tubes Fins Segmented fins

20. Top fired Bottom fired Side fired

21. Gas firing Oil firing Oil + Gas firing

22. Burner Type Function Advantages Premix Gas Gas and air are thoroughly mixed before combustion. Results in a more complete combustion. Lower emissions of CO and unburned hydrocarbons. Can achieve a uniform flame shape. Raw Gas / Oil Fuel is injected directly into the combustion chamber without pre-mixing. Simple design, easy to operate and maintain. High turndown ratio. Flexible regarding fuel quality. Staged Fuel “Low NOx” Fuel supply is divided into stages to control the combustion process. Reduces peak flame temperature. Lowers NOx emissions due to staged combustion. Can be retrofitted into existing systems. Staged Air “Low NOx” Air supply is divided into stages, with primary and secondary air streams. Controls the mixing rate of air and fuel. Reduces thermal NOx formation. Achieves lower NOx emissions without affecting flame stability. Fuel Gas Recirculation “Low NOx” A portion of the flue gas is recirculated and mixed with fresh air before combustion. Lowers oxygen concentration and flame temperature. Significantly reduces NOx emissions. Improves heat transfer due to increased gas volume.

23. Burners

24. Raw Gas/ Oil Burner

25. Staged Fuel Burners

26. Staged Air Burner

27. Flue Gas Recirculation Burner(FGR)

28. Burner Classification NOx Emissions Mechanisms Design Advantages Low NOx Burner Less than 50 ppm Staged air and fuel introduction, Internal flue gas recirculation Moderate reduction in NOx emissions, Can be retrofitted into existing systems, Improved fuel/air mixing Ultra-Low NOx Burner 20-50 ppm Advanced staged combustion, External flue gas recirculation, Low NOx burner tips Significant reduction in NOx emissions, More complex design for better control over combustion, Can meet stricter regulations Next Generation/New Technology Burner Less than 10 ppm Innovative low-NOx combustion technologies, Precision combustion control systems, NOx reduction catalysts Superior reduction in NOx emissions, Utilizes state-of-the-art technology, May incorporate real-time monitoring and adjustments

29. Burner Classification NOx Emissions Mechanisms Simplified Explanation Design Advantages Next Generation/New Technology Burner Less than 10 ppm Innovative low-NOx combustion technologies These burners use cutting-edge technologies to control the combustion process and reduce NOx emissions. Superior reduction in NOx emissions, Utilizes state-of-the-art technology, May incorporate real-time monitoring and adjustments Precision combustion control systems They have precise control systems that monitor and adjust the combustion process in real-time. NOx reduction catalysts They use catalysts that chemically convert NOx in the exhaust gases into harmless substances before they are released into the atmosphere.

30. Understanding Heat Flux and Its Impact on Heaters High heat flux refers to the scenario where a substantial amount of heat is transferred through a relatively small area. In the context of heaters, this could potentially lead to operational issues. Hot Spots: Areas hotter than others due to high heat flux. Material Stress: Hot spots cause uneven expansion, leading to stress. Reduced Life: Stress from hot spots can cause material fatigue, reducing heater life. In essence, managing heat flux and hot spots is key for heater longevity.

31. The Role of Excess Air in Burners Premix Burners: These burners mix fuel and air before combustion, allowing for complete combustion over a larger area with less intense heat, reducing peak flame temperature and NOx formation. Non-Premix Burners: If the burner can’t mix fuel and air adequately before combustion, adding excess air may not cool the system and could lead to higher flame temperatures. Incomplete Mixing: Without premixing, excess air can create pockets of fuel-rich combustion, leading to localized hot spots with higher temperatures. Excess Oxygen: If not properly mixed, excess oxygen can increase the overall flame temperature. Higher Exhaust Temperatures: If excess air doesn’t absorb enough heat due to poor mixing, it can contribute to higher exhaust temperatures, implying higher flame temperatures and reduced system efficiency. The key takeaway is that effective premixing of air and fuel is crucial when using excess air to lower flame temperature and reduce NOx emissions. Without it, adding excess air could increase NOx emissions due to higher flame temperatures.

32. High Turndown Ratio in Fire Heaters 1. Efficiency and Control High turndown ratio allows the burner to operate at lower power levels without turning off. Provides better stability and control. Improves steam pressure stability, helping your burner heat more evenly. 2. Reduced Wear and Tear High turndown burners can reduce the number of on-off cycles. Reduces wear and tear on the burner. Increases burner lifespan. 3. Energy Savings High turndown burners can match the energy input to the actual heating load. Improves seasonal efficiencies. Less fuel is burned, resulting in better unit efficiency. 4. Safety High turndown ratios can prevent power fluctuations. Maintains proper steam pressure and water temperature. Leads to safer operation of the fire heater. Note Different burners have different compressor calculations, so one burner may have a higher ratio than another. The burner with the higher ratio will have more flexibility.

33. Strategies for Reducing NOx Emissions in Fired Heaters The formation of Nitrogen Oxides (NOx) is a significant issue in fired heaters due to its environmental impact. The key to reducing NOx emissions lies in disrupting radiant heat transfer, as NOx formation is highly dependent on flame temperatures in the radiant section. Techniques for Reducing Peak Flame Temperatures Several techniques aim to reduce peak flame temperatures, thereby lowering thermal NOx production, which increases exponentially with temperature. These techniques include: Flue Gas Recirculation (FGR) : This method involves recycling flue gas to the burner. The recycled gas absorbs heat and reduces oxygen availability, both of which lower the flame temperature. Excess Air or Lean Premixed Combustion : This technique dilutes the combustion zone with extra air, limiting temperatures. Goal The ultimate goal of these strategies is to minimize NOx emissions while maintaining combustion stability and efficiency. Conclusion Most NOx reduction techniques indirectly target radiant heat transfer to the tubes, as the driving factor is high temperatures in the radiant section. By lowering these temperatures through combustion dilution, we can decrease NOx production without drastically impacting radiant transfer.

34. best practices are key to preventing and mitigating these types of malfunctions in fire heaters Malfunction Type Characteristics Common Causes Effects on Heater Performance Mitigation Strategies Foulants Deposits of foreign material not normally produced by the combustion process Poor quality fuel; Corrosion products; Ingress of dirt or debris Reduced heat transfer; Potential corrosion; Reduced efficiency Pre-treatment of fuel; Filtration; Regular cleaning and maintenance Soot Fine black particles composed mostly of carbon; Byproduct of incomplete combustion Insufficient air supply; Poor fuel atomization; Low combustion temperatures Increased emissions; Reduced efficiency; Potential safety hazards Proper burner adjustment; Regular maintenance; Air-to-fuel ratio control Coke Solid carbon-based deposits; Heavier and more dense than soot Extremely high temperatures; Poor fuel quality; Long residence times in high-temperature zones Blocked passages; Reduced heat transfer; Increased pressure drop Optimal burner operation; Adequate fuel quality; Regular decoking procedures

35. Feature Mechanical Pigging Chemical Cleaning Soot Blowing Principle Uses physical devices (pigs) to scrape off coke. Uses chemical solutions to dissolve or loosen coke. Uses pressurized steam or air to blow away soot. Complexity Relatively simple operation. May require precise chemical formulations. Simple operation, often automated. Downtime Can be quicker to perform, less downtime. May require longer downtimes for soaking. Can be performed online without downtime. Effectiveness Highly effective for physical removal of coke. Effectiveness depends on chemical reaction rates. Effective for loose deposits, not for hard coke. Equipment Wear Can cause wear to the tubes and pigs themselves. Typically gentle on equipment, less physical wear. Minimal wear, regular use prevents deposit buildup. Environmental Impact Low chemical impact, but requires disposal of coke. Chemical disposal and neutralization needed. Low impact, uses steam or compressed air. Safety Risks Physical risks to operators, potential for tube damage. Handling of chemicals, potential for hazardous exposure. High-pressure steam or air poses safety risks. Post-Cleaning Procedure Usually requires inspection and potential repair. May need neutralization and thorough rinsing. Generally does not require follow-up procedures. Cost Cost-effective for accessible systems. Can be costly due to chemicals and neutralization. Low operational costs, but requires installation. Scale of Application Suitable for large and accessible systems. May be preferred for intricate or smaller systems. Common in boilers, not suitable for coked tubes. Repeatability Can be repeated, but wear is a concern. Can be repeated as needed with proper handling. Designed for regular use to maintain cleanliness. Residue Physical residue needs to be collected. Chemical residue needs to be neutralized. Non

36. Decoking

37. Heater Tube Decoking (Pig Decoking)

38. Soot blowers

39. Control System Type Description Design Advantages Example Illustrating Design Advantages Manual Control Human operators adjust controls based on readings and experience. Low complexity, Direct human oversight, Flexible to immediate human judgment Operators can make rapid adjustments during startup or shutdown of a small fired heater based on their expertise. Single-Loop Control Automated control with a single feedback loop for each control point. Autonomous operation, Consistent control for single variables, Easier troubleshooting A single-loop controller maintains the fuel-to-air ratio on a fired heater, keeping the combustion process stable. Programmable Logic Controllers (PLC) Digital computers used for automation of industrial processes. High reliability, Real-time response, Suitable for discrete and analog control A PLC rapidly shuts down a fired heater if unsafe conditions are detected, protecting the equipment and plant. Distributed Control Systems (DCS) A system with multiple controllers distributed throughout the plant. Integrated control environment, High scalability, Advanced data analysis and reporting A DCS manages multiple heating zones within a large fired heater, optimizing overall thermal performance. Advanced Process Control (APC) Systems that use model-based algorithms to optimize performance. Enhanced process optimization, Reduced process variability, Energy and cost savings APC adjusts the operation of a fired heater in response to changing feedstock properties to maximize efficiency. Feedforward Control Controls that react to measured disturbances before they affect the process. Preemptive correction of disturbances, Reduced process upsets, Can be combined with feedback control Feedforward control adjusts fuel flow in anticipation of changes in the feed rate, preventing temperature swings. Adaptive Control Control systems that adjust their parameters in real-time based on process behavior. Self-tuning during process changes, Improved performance over time, Resilience to process drift An adaptive control system learns the heat absorption characteristics of a fired heater and adjusts control strategy accordingly. APC with Model Predictive Control (MPC) Advanced control that uses a predictive model to optimize several control loops simultaneously. Multivariable control strategy, Anticipates future disturbances, Optimizes control moves for minimal variance MPC anticipates downstream demand changes and adjusts the heat input to the fired heater to meet these changes efficiently.

40. Condition Symptoms Possible Causes Troubleshooting Steps Excess Air (Lean Burn) Low flame temperature Burner air gates too open Adjust air gates to reduce air intake High stack temperature Incorrect air/fuel ratio setting Recalibrate air/fuel ratio controls Low CO and high O2 in flue gas Leaks in air preheater or ducting allowing extra air in Inspect and repair leaks Reduced heater efficiency Inadequate fuel supply Check and ensure proper fuel delivery Light-colored flame Excess air diluting flame color Adjust air-to-fuel ratio to achieve proper flame characteristics Increase in NOx emissions Higher combustion temperatures and excess oxygen Optimize combustion conditions to lower peak flame temperatures

41. Condition Symptoms Possible Causes Troubleshooting Steps Excess Fuel (Rich Burn) High flame temperature Burner fuel gates too open Adjust fuel gates to reduce fuel intake Soot formation in stack Incorrect air/fuel ratio setting Recalibrate air/fuel ratio controls High CO and low O2 in flue gas Clogged air filters or air intake restrictions Clean filters and remove obstructions Increased risk of combustion-generated pollutants Insufficient combustion air supply Increase combustion air, check for obstructions Yellow or orange flame Incomplete combustion due to lack of oxygen Increase air supply or improve mixing Unburned fuel smell Excess fuel not being combusted Check for proper ignition and flame stability Visible smoke from stack Particulates from incomplete combustion Ensure complete combustion; check for proper draft

42. Condition Symptoms Possible Causes Troubleshooting Steps Ununiform Flame Fluctuating flame temperature Inconsistent fuel supply Stabilize fuel delivery systems Striations or clear zones in flame Poor fuel/air mixing Adjust mixing mechanisms for better homogenization Localized overheating Burner damage or malfunction Inspect burners for damage and ensure they are operating correctly Vibration or rumble in heater Unstable combustion dynamics Analyze combustion dynamics and stabilize flame Pulsating or dancing flame Air flow turbulence Check for obstructions or irregularities in air flow paths; adjust dampers Areas of different color within flame Variations in combustion conditions across the flame Ensure even distribution of air and fuel; assess for burner orifices obstruction

43.  Various Routine Inspections And Maintenance Tests For Fire Heaters Test Name Function Mechanism Usage Conditions Flame Test Evaluates the burner flame’s condition Involves a visual check of the flame’s color, shape, and pattern to spot any unusual combustion characteristics. Should be carried out regularly during operation under stable conditions for optimal burner performance. Flash Light Test Checks for leaks or structural integrity Utilizes a flashlight to visually inspect the heater’s interior surfaces for cracks, leaks, or damage, especially in dark areas. Should be performed when the unit is cool and safe to enter, typically during shutdown periods. Water Spray Test Verifies the integrity of refractory lining Involves spraying water onto the heater’s exterior and watching for rapid evaporation, which could indicate hot spots due to refractory failure. Should be done when the heater is shut down and cooled, to prevent thermal shock to the structure. CO Test Monitors for incomplete combustion Measures the concentration of carbon monoxide in the flue gases as an indicator of combustion efficiency. Can be performed routinely during operation or in response to suspected issues with fuel combustion. AGA Test Ensures appliance safety and efficiency The American Gas Association (AGA) test is a series of standardized assessments designed to verify appliance safety, performance, and efficiency. Should be scheduled as required by industry standards or regulations, often annually, or after significant repairs or modifications.

44. key components involved in an AGA test for fire heater inspections Component Description Safety Inspections Inspections for leaks, proper assembly, and installation to avoid fires or gas problems. Performance Testing Assessment of burner operation, flame quality, and heat distribution. Efficiency Measurements Determination of the fuel-to-heat conversion ratio and comparison with efficiency standards. Emission Checks Measurement of CO, NOx, and other flue gas levels to ensure they are within acceptable limits. Control Systems Analysis Testing of controls and safety devices such as thermostats and pressure regulators. Ventilation and Flue Inspection Inspection of the flue for blockages and verification of proper venting to the outside. Documentation Review Review of operating manuals, maintenance records, and previous inspection reports.