8 ENERGY LOSS POINTS THAT INCREASE BOILER FUEL CONSUMPTION AND HOW TO FIX THEM

Prepared by: DIVI Group Technical Team

Technical Review: Engineer Le Van Hieu – Founder and CEO of DIVI Group

Many businesses assume that rising steam production costs are mainly caused by higher fuel prices. In reality, many boiler systems are still wasting a significant amount of energy every day without operators realizing it.

These losses often occur gradually and do not cause the boiler to stop immediately. However, they can steadily increase fuel consumption over time.

In this article, DIVI Group analyzes eight energy loss points that increase boiler fuel consumption, while identifying their causes and practical solutions to help businesses improve operating efficiency. 

I. How to Identify Energy Loss in a Boiler System

Many businesses only realize that their boiler is consuming excessive fuel when steam production costs become noticeably higher.

In reality, energy loss often develops gradually and can be difficult to detect without regularly monitoring operating parameters.

A boiler system may still maintain the required steam pressure and output while its efficiency has already declined significantly due to several energy loss points occurring at the same time.

For this reason, regularly monitoring operating data is essential for identifying abnormal conditions early and implementing corrective action in a timely manner.

Common warning signs include:

• Flue gas temperature increasing compared with the system’s stable operating period. 

• Fuel consumption increasing without a corresponding increase in steam output. 

• O₂ or CO levels in the flue gas showing an upward trend. 

• Make-up water consumption increasing abnormally because of condensate loss or leakage. 

• Steam pressure fluctuating or the boiler frequently needing to increase load to meet production demand. 

• Wet steam, condensate accumulation, or water hammer occurring in the steam pipeline. 

• TDS or other boiler water quality parameters fluctuating. 

• Boiler feedwater temperature falling below normal levels. 

• Leakage occurring at pipelines, valves, or steam traps. 

If one or more of these signs appear, the entire boiler system should be inspected to identify the actual cause.

In many cases, higher steam production costs are not caused by one single factor, but by several energy loss points existing simultaneously.

II. Energy Loss #1: Poorly Optimized Combustion Process

The combustion process is the first stage that determines how much heat can be extracted from the fuel.

If the fuel does not burn completely or the combustion air supply is unsuitable, part of the energy is lost inside the furnace before it can be transferred to the water for steam generation.

In many cases, the boiler can still produce enough steam for production but consumes more fuel because the combustion conditions have not been properly optimized.

1. Excessive O₂ Increases Heat Loss

A boiler requires a certain amount of air to ensure complete combustion.

However, if too much air is supplied, the volume of hot flue gas leaving the system increases, carrying more heat into the environment.

Excessive air can also:

• Increase flue gas flow. 

• Increase the amount of heat discharged through the stack. 

• Increase electricity consumption by the FD fan and ID fan. 

• Reduce the combustion-zone temperature. 

• Make the combustion process less stable. 

Conversely, if the air supply is too low, the fuel will not burn completely, resulting in higher CO levels or unburned carbon remaining in the ash.

Therefore, the objective is not to supply as much air as possible, but to maintain the appropriate air level for each fuel type and operating condition.

2. Air Infiltration Reduces Boiler Efficiency

In addition to the air supplied by the fan, outside air may enter the system through unsealed areas.

Common leakage points include:

• Cleaning doors. 

• Fuel feeding doors. 

• Rotary valves. 

• Ash hoppers. 

• Joints along the flue gas path. 

• Furnace doors. 

This infiltrated air does not contribute effectively to combustion, but it still increases flue gas flow.

As a result, more heat is lost through the stack, and combustion control becomes more difficult.

Therefore, checking the airtightness of the entire system is just as important as adjusting the combustion air fan.

3. Incomplete Combustion Causes Energy Loss

A portion of the fuel may remain unburned and leave the system with the ash or flue gas.

This type of energy loss is often difficult to identify through visual inspection alone.

Signs that should be checked include:

• High CO levels in the flue gas. 

• A high amount of unburned carbon remaining in the ash. 

• Unstable flame conditions. 

• Fluctuating steam pressure even though the fuel feed rate remains unchanged. 

Possible causes include:

• Improper air distribution. 

• High fuel moisture content. 

• Uneven fuel size. 

• An unsuitable fuel-bed thickness. 

• Insufficient residence time in the furnace. 

• Unstable combustion-zone temperature. 

4. Fuel Quality Directly Affects Combustion Efficiency

For biomass-fired boilers, fuel quality has a major impact on the combustion process.

Key factors that should be controlled include:

• Moisture content. 

• Heating value. 

• Fuel size. 

• Ash content. 

• Impurities. 

• Fuel consistency. 

• Storage conditions. 

When fuel quality changes continuously, combustion conditions change as well.

This makes it more difficult to adjust the air supply, fuel feed rate, and steam pressure, while also increasing the risk of energy loss.

Note: There is no single excess O₂ value or flue gas temperature that is suitable for every boiler. These parameters must be evaluated based on furnace technology, fuel type, operating load, and the configuration of heat recovery equipment in each system.

Solutions to Reduce Combustion Energy Loss

To improve combustion efficiency and reduce boiler fuel consumption, businesses should:

• Adjust the combustion air supply to match operating conditions. 

• Inspect and repair all air infiltration points. 

• Control incoming fuel quality. 

• Regularly monitor O₂, CO, and flue gas temperature. 

• Inspect ash conditions to assess the completeness of fuel combustion. 

Optimizing the combustion process not only reduces fuel consumption but also creates the foundation for energy-saving solutions in the following stages to perform effectively.

III. Energy Loss #2: Excessively High Flue Gas Temperature

After the combustion process, part of the heat generated is transferred to the boiler water to produce steam, while the remaining heat leaves the system with the flue gas.

The higher the flue gas temperature, the more unused heat is being discharged into the atmosphere. This means the boiler is losing part of the energy generated from the fuel instead of utilizing it for steam production. 

Why Does High Flue Gas Temperature Cause Energy Loss?

For many biomass boiler systems equipped with an economizer or an air preheater (APH), the flue gas temperature is typically maintained within the range of 130–170°C.

The optimum flue gas temperature should be determined based on several factors, including: Fuel type, fuel moisture content, boiler feedwater temperature, excess O₂ level, flue gas dew point limitation

Example: When the flue gas temperature is reduced from 220°C to 160°C, the amount of heat recovered depends on the flue gas flow rate, flue gas composition, and excess O₂ level.

Therefore, the improvement in boiler efficiency should always be calculated using actual operating data rather than applying a fixed efficiency gain to every boiler system.

However, in many operating plants, flue gas temperatures still reach 250–300°C. This is a clear indication that a significant amount of heat is escaping through the stack instead of being used to generate steam.

As a result, the boiler must consume more fuel to maintain the same steam production rate.

Operating Parameters That Should Be Checked

A high flue gas temperature alone is not sufficient to conclude that boiler efficiency has decreased.

The following operating parameters should be evaluated together:

Parameter	Purpose
Flue gas temperature at different measurement points	Identify areas with excessive heat loss or poor heat transfer
Flue gas O₂ concentration	Evaluate excess combustion air
Flue gas CO concentration	Assess combustion completeness
Boiler feedwater temperature before and after the economizer	Evaluate heat recovery performance
Differential pressure across heat transfer surfaces	Detect fouling or blockage
Fuel moisture content and fuel quality	Evaluate their impact on flue gas volume and heat loss
Ash deposits and scale formation	Assess resistance to heat transfer

Note: A high flue gas temperature does not necessarily indicate poor performance of the heat recovery equipment alone.
In many cases, it is caused by a combination of factors such as fouled heat transfer surfaces, scale formation, excessive excess O₂, air leakage, and inconsistent fuel quality.

Solutions to Reduce Heat Loss Through the Flue Gas System

To control flue gas temperature and improve heat utilization, it is recommended to:

• Monitor flue gas temperature at key measurement points. 

• Clean heat transfer surfaces regularly. 

• Inspect for scale formation on the water side. 

• Evaluate the performance of the economizer and air preheater (APH). 

• Monitor differential pressure across the flue gas path. 

• Measure O₂ and CO concentrations to eliminate combustion-related causes. 

• Control fuel moisture content and maintain consistent fuel quality. 

If the flue gas temperature increases significantly compared with the system's normal operating condition, the root cause should be investigated before simply increasing the fuel feed rate to maintain steam production.

When higher flue gas temperature is accompanied by increased fuel consumption, both heat transfer efficiency and the condition of heat transfer surfaces—including ash deposits and scale buildup—should be evaluated.

The economizer and air preheater recover waste heat from the flue gas to preheat boiler feedwater and combustion air

IV. Energy Loss #3: Inefficient Boiler Blowdown

Boiler blowdown is an essential operation used to remove accumulated impurities and maintain proper boiler water quality.

However, if blowdown is not carried out correctly, it can become a significant source of energy loss. 

Two Common Blowdown Mistakes

Insufficient Blowdown	Excessive Blowdown
Scale accumulation	Loss of hot boiler water
Reduced heat transfer efficiency	Loss of thermal energy
Increased boiler fuel consumption	Loss of water treatment chemicals

Both situations gradually increase the overall cost of steam production.

Why Should Blowdown Be Controlled Based on TDS?

Every time a boiler is blown down, the system not only removes impurities but also loses:

• Hot boiler water. 

• Thermal energy. 

• Boiler water treatment chemicals. 

For this reason, boiler blowdown should not be performed based solely on operator experience or fixed routines. Instead, it should be controlled according to the TDS (Total Dissolved Solids) level to achieve the proper balance between boiler water quality and energy conservation.

The recommended boiler water TDS depends on several factors, including:

• Boiler operating pressure. 

• Boiler type. 

• Boiler feedwater quality. 

• Required steam quality. 

• Equipment manufacturer's recommendations. 

For many low-pressure industrial boilers, the recommended TDS range is typically 2,000–3,000 mg/L.

In addition to TDS, a comprehensive boiler water treatment program may also monitor:

• pH 

• Alkalinity 

• Water hardness 

• Silica 

• Phosphate 

• Sulfite 

• Chloride 

• Oil and grease 

• Electrical conductivity 

The specific parameters that need to be monitored depend on the boiler type, operating pressure, water treatment program, and required steam quality.

Example: For a boiler producing 10 tons of steam per hour, reducing the blowdown rate from 10% to 5% decreases the blowdown water volume from approximately 1 ton per hour to 0.5 ton per hour, assuming all other operating conditions remain unchanged.

The actual savings in thermal energy, water, and water treatment chemicals should be calculated based on the blowdown water temperature, operating hours, and the actual water quality.

If your company is developing or improving its boiler operating procedures, the article Proper Boiler Blowdown Procedure provides detailed guidance on when and how blowdown should be performed.

Monitoring boiler blowdown based on the TDS level removes impurities while minimizing the loss of hot water and thermal energy

V. Energy Loss #4: Energy Loss in the Steam Distribution and Condensate System

After steam is generated, it must be delivered to the end-use equipment at a stable pressure and flow rate. However, the steam distribution system may contain several sources of energy loss, such as steam leaks, inefficient steam traps, or condensate that is discharged instead of being recovered.

Although these issues have different causes, they all increase boiler fuel consumption and steam production costs if they are not detected and corrected in time. 

Steam Leaks Increase Fuel Consumption

A small steam leak may not have a noticeable impact in the short term. However, when multiple leaks exist and remain unrepaired over time, the amount of steam loss gradually becomes significant.

In addition to losing steam, the system also experiences a pressure drop, forcing the boiler to burn more fuel to compensate for the lost steam.

This represents an additional operating cost that many businesses fail to recognize because the boiler system continues to operate normally.

Inefficient Steam Trap Operation

A steam trap is designed to discharge condensate while retaining live steam within the system.

A steam trap that fails in the open position may allow live steam to escape directly into the condensate return line. In this case, the system continuously loses steam even though the loss may not be obvious from the outside.

Conversely, a blocked steam trap prevents condensate from being discharged properly. Condensate accumulating in equipment or pipelines may:

• Reduce heat transfer efficiency. 

• Cause temperature fluctuations. 

• Increase the risk of water hammer. 

• Affect valves and steam-consuming equipment. 

Therefore, steam trap inspections should distinguish between live steam leakage and condensate blockage, rather than simply checking for external leakage.

Regular inspection of steam trap performance is an important part of any steam system energy-saving program.

Failure to Recover Condensate

In addition to steam leaks, many factories still discharge condensate directly instead of recovering and reusing it.

However, condensate still contains a considerable amount of thermal energy. If it is not recovered, all of this energy is wasted.

Although the daily energy loss may appear relatively small, it can accumulate into a significant operating cost over months or years.

Solutions to Reduce Energy Loss

To minimize this type of energy loss, it is recommended to:

• Inspect all steam leakage points throughout the system. 

• Recover condensate for reuse within the boiler system. 

One solution that has been widely adopted by many businesses is condensate recovery. DIVI Group has analyzed this solution in detail in the following article: PCHR – A Solution for Reducing Boiler Fuel Costs

Thu hồi nước ngưng giúp tận dụng lại nguồn nước và nhiệt năng trước khi đưa trở lại nồi hơi

VI. Energy Loss #5: Heat Loss Caused by Ineffective Insulation

In a boiler system, steam and hot water always carry a significant amount of thermal energy. If the equipment or piping is not properly insulated, heat will continuously be lost to the surrounding environment.

This is one of the easiest forms of energy loss to observe, yet it is often overlooked during daily operation.  

1. Common Areas Where Heat Loss Occurs

Heat loss can occur at various locations throughout the boiler system, including:

• The boiler body. 

• Steam pipelines. 

• Hot water pipelines. 

• Valves, flanges, and auxiliary equipment. 

• Areas where the insulation has been damaged or no longer provides adequate thermal protection. 

When these components continuously release heat into the surrounding environment, part of the energy generated from the fuel is no longer available for steam production.

2. Inspect and Maintain Insulation Regularly

To minimize heat loss, the condition of the insulation throughout the entire system should be inspected regularly.

Any insulation that has become detached, damaged, or deteriorated should be repaired or replaced promptly to maintain the thermal retention performance of the equipment and piping.

Regular insulation maintenance not only reduces energy loss but also helps maintain stable operating efficiency throughout the entire boiler system. 

Do Not Overlook Small Sources of Heat Loss

Many businesses focus primarily on reducing fuel consumption inside the furnace while paying little attention to heat being lost from pipelines and auxiliary equipment.

Regular inspection of the insulation system helps identify deteriorated areas at an early stage, thereby reducing energy loss and lowering steam production costs during operation.

VII. Energy Loss #6: Poor Control of Boiler Feedwater and Boiler Water Quality

Water quality is one of the key factors that directly affects boiler efficiency, operational safety, and equipment lifespan.

Boiler water treatment is not limited to the use of water treatment chemicals. It includes the entire water treatment program, from feedwater treatment, water softening, deaeration, pH adjustment, boiler water quality control, to blowdown management during operation.

If any part of this process is not properly controlled, scale formation and corrosion may develop inside the boiler system, reducing heat transfer efficiency, increasing boiler fuel consumption, and leading to higher maintenance costs.

Saving on Water Treatment Chemicals Today May Increase Costs Tomorrow

Many businesses believe that eliminating boiler water treatment chemicals can reduce operating costs.

However, the money saved is often far less than the additional costs caused by scale buildup, corrosion, increased fuel consumption, and equipment repairs in the future. 

Both Scale and Corrosion Reduce Boiler Performance

When scale forms on heat transfer surfaces, heat transfer efficiency decreases, forcing the boiler to consume more fuel to produce the same amount of steam.

Meanwhile, corrosion reduces equipment durability, increases maintenance requirements, and shortens the service life of the boiler system.

Water Treatment Solutions

To minimize both scale formation and corrosion, businesses should:

• Treat boiler feedwater before it enters the boiler. 

• Use appropriate boiler water treatment chemicals. 

• Continuously monitor boiler water quality throughout operation. 

Learn more: Boiler Feedwater Treatment

Scale buildup and corrosion reduce heat transfer efficiency, increase fuel costs, and shorten the service life of the boiler

VIII. Energy Loss #7: Boiler Design and Operating Load Are Not Properly Matched

A high-efficiency boiler system depends not only on equipment quality but also on selecting the appropriate boiler capacity and maintaining stable operating conditions.

In practice, many businesses install boilers with capacities significantly larger than their actual steam demand or oversize the system in anticipation of future expansion.

Once production reaches stable operation, the actual steam consumption is often much lower than the original design capacity.

As a result, the boiler operates at low load for extended periods, reducing fuel utilization efficiency and increasing steam production costs.

1. Operating at Low Load Reduces Boiler Efficiency

Most industrial boilers achieve their highest efficiency when operating close to their rated capacity.

If a boiler frequently operates at low load, maintaining optimal combustion conditions becomes more difficult.

Combustion becomes less stable, causing the boiler to consume more fuel while producing the same amount of steam.

This can be compared to driving a car.

When a vehicle travels steadily on a highway at a constant speed, fuel consumption is generally lower.

In contrast, frequent acceleration, deceleration, or prolonged low-speed driving increases fuel consumption.

A boiler operates in a similar way.

When it runs steadily at an appropriate operating load, it utilizes fuel energy more efficiently.

However, prolonged operation at low load reduces efficiency and gradually increases steam production costs.

2. Fluctuating Steam Demand

Besides low-load operation, many factories also experience unstable steam demand.

During production, multiple process lines may consume steam simultaneously, then later reduce their load or stop operating.

As steam demand continuously changes, the boiler must repeatedly increase and decrease its output to match the varying load.

These frequent operating changes make it difficult to maintain stable combustion, reducing boiler efficiency and increasing fuel consumption.

This is one of the most common forms of hidden energy loss and is often difficult to identify by monitoring steam production alone.

Solutions to Reduce Energy Loss Caused by Improper Operating Load

To improve fuel utilization efficiency, businesses should:

• Select a boiler capacity that matches the actual steam demand. 

• Monitor the operating load after the plant reaches stable production. 

• Adjust the fuel feed rate and combustion air according to the actual load. 

• Optimize the combustion process to maintain stable boiler efficiency. 

• Re-evaluate the system whenever steam demand changes significantly. 

Maintaining boiler operation under conditions that match the original design allows combustion to remain more stable, improves fuel utilization efficiency, and reduces long-term steam production costs.

IX. Energy Loss #8: Steam Quality and the Boiler Feedwater System Are Not Optimized

Once steam is generated by the boiler, the objective is to deliver as much thermal energy as possible to the end-use equipment.

However, if the steam contains excessive moisture, condensate is not removed promptly, or the feedwater is not properly preheated and deaerated, the overall energy efficiency of the steam system will decrease.

These forms of energy loss often occur gradually and receive little attention, yet they directly affect operating efficiency, equipment lifespan, and steam production costs.

1. Wet Steam Reduces Steam Utilization Efficiency

Saturated steam leaving the boiler may still contain a certain amount of water. In addition, as steam travels through the piping system, it loses heat and continues to condense.

If this condensate is not separated from the steam flow, the steam supplied to the end-use equipment will have lower quality, reducing heat transfer efficiency and steam utilization.

Common Causes

• Water carryover from the steam drum. 

• Condensate formed in the steam piping due to heat loss. 

• Insufficient condensate drainage points. 

• Steam separators are not installed where required. 

Consequences

When steam contains excessive moisture, the system may experience:

• Reduced heat transfer efficiency at steam-consuming equipment. 

• Longer heating time. 

• Higher steam consumption to achieve the same heating performance. 

• Increased risk of water hammer in the piping system. 

• Shortened service life of valves, heat exchangers, and other steam system components. 

Solutions

• Install condensate drainage points at appropriate locations throughout the steam piping. 

• Regularly inspect the operating condition of steam traps. 

• Install Steam Separators where necessary, especially upstream of pressure-reducing valves or equipment requiring dry steam. 

Improving steam quality not only enhances heat transfer efficiency but also helps reduce steam consumption during production. 

Read more: The Role of Steam Separators in Improving Steam Quality and Reducing Condensate in Steam Pipelines

A steam separator removes entrained water from the steam before it is delivered to steam-consuming equipment

2. Preheating Boiler Feedwater Improves Energy Utilization

After condensate is recovered and returned to the system, the boiler feedwater should be preheated before entering the boiler.

The higher the feedwater temperature, the less heat the boiler must supply to produce steam.

This allows the system to make better use of the available thermal energy and reduces boiler fuel consumption.

Feedwater preheating is commonly achieved by recovering heat from condensate or through heat recovery equipment such as an economizer.

3. Deaeration Helps Prevent System Corrosion

Boiler feedwater always contains dissolved gases, particularly oxygen (O₂) and carbon dioxide (CO₂).

If these gases are not removed before the water enters the boiler, they can accelerate corrosion in:

• The steam drum. 

• Piping. 

• Storage tanks. 

• Boiler feedwater pumps. 

• Other equipment throughout the system. 

Corrosion not only shortens equipment life but also increases maintenance costs and the risk of unexpected failures during operation.

4. The Deaerator Stabilizes the Entire Feedwater System

A deaerator not only removes dissolved gases but also plays an important role in stabilizing the entire boiler feedwater system.

It helps to:

• Preheat boiler feedwater before it enters the boiler. 

• Remove dissolved oxygen and carbon dioxide. 

• Receive and mix returned condensate with make-up water. 

• Maintain a stable water supply for the boiler feedwater pumps. 

As a result, the feedwater system operates continuously, reduces operating fluctuations, and improves overall energy efficiency.

If your company would like to learn more about the design and operating principles of a deaerator, please refer to the following article: Benefits of a Deaerator Tank in Boiler Systems 

Items That Should Be Inspected Regularly

To minimize energy loss during steam distribution and boiler feedwater supply, the following items should be inspected regularly:

• Steam quality at steam-consuming equipment. 

• Operating condition of steam separators and steam traps. 

• Condensate drainage performance throughout the piping system. 

• Condensate recovery rate. 

• Boiler feedwater temperature before entering the boiler. 

• Operating condition of the deaerator. 

• Efficiency of dissolved gas removal from the feedwater. 

Monitoring all of these factors together helps improve steam quality, maximize the use of available thermal energy, and maintain stable long-term boiler system performance.

X. Priority Table for Energy Loss Reduction Solutions

Not all energy-saving solutions need to be implemented at the same time. In practice, businesses should prioritize addressing the causes that require a relatively low investment but deliver significant results before considering larger-scale improvement projects.

Setting the right priorities helps reduce steam production costs in the short term while optimizing investment budgets and minimizing the impact on production activities.

Solution	Investment Level	Potential Effectiveness	Recommended Priority
Optimize the combustion process (O₂, CO, combustion air supply)	Low	Very High	When excess O₂ is high, CO increases, or fuel is not completely burned
Repair steam leaks and inspect steam traps	Low	Very High	When steam pressure drops, condensate volume is abnormal, or steam leaks are detected
Optimize boiler blowdown based on TDS	Low	High	When TDS exceeds the recommended limit or blowdown is performed based on operator experience
Clean heat transfer surfaces and remove scale deposits	Low - Medium	High	When flue gas temperature increases or fuel consumption gradually rises
Repair or improve insulation	Low	Medium	When pipelines, valves, or equipment surfaces release excessive heat
Recover condensate	Medium	High	When condensate is discharged instead of being recovered or when the condensate recovery rate is low
Inspect and clean the Economizer and Air Preheater	Medium	High	When flue gas temperature is high or heat recovery equipment is operating inefficiently
Improve fuel quality	Low - Medium	Medium to High	When fuel moisture, particle size, or heating value is inconsistent
Upgrade the control system and optimize operating load	Medium - High	Depends on the system	When the boiler frequently operates outside its designed load range
Retrofit or replace the boiler	High	Depends on the system condition	When the existing system no longer meets technical requirements or its efficiency is too low

Note: The effectiveness shown in the table is for reference only. Actual results depend on the boiler technology, fuel type, boiler capacity, operating conditions, and the current condition of each system.

XI. Boiler System Inspection Checklist

After identifying potential energy loss points, the next step is to inspect the entire boiler system to determine the root causes and select the most appropriate solutions.

The inspection should not focus on a single piece of equipment. Instead, it should evaluate the complete process, including combustion, heat transfer, steam generation, steam distribution, condensate recovery, and boiler feedwater treatment.

Inspection Item	Evaluation Criteria	Objective
Combustion process	O₂ concentration, CO concentration, fuel combustion condition, and unburned carbon in the ash	Maintain stable combustion and maximize the utilization of fuel energy
Flue gas system	Flue gas temperature, Economizer performance, Air Preheater performance, and fouling on heat transfer surfaces	Reduce heat loss through the flue gas system
Boiler blowdown	TDS level, blowdown frequency, and blowdown rate	Maintain boiler water quality while minimizing heat loss
Steam distribution system	Steam leaks, steam trap condition, and water hammer	Reduce steam loss and maintain steam quality
Condensate system	Condensate recovery rate and condensate return temperature	Recover remaining thermal energy and reduce make-up water consumption
Insulation	Pipelines, valves, flanges, and damaged insulation	Minimize heat loss to the surrounding environment
Boiler feedwater and boiler water	pH, TDS, water hardness, and other water quality parameters required by the treatment program	Reduce scale formation and corrosion while maintaining efficient heat transfer
Operating load and fuel	Boiler operating capacity, load level, fuel moisture content, and fuel quality	Ensure the boiler operates under conditions suitable for its design
Steam quality and feedwater system	Steam moisture content, condensate separation performance, feedwater temperature, and deaerator condition	Improve steam utilization efficiency and stabilize the feedwater system

Note: Not every boiler system requires the same level of inspection for every item. The inspection scope should be determined based on the boiler type, fuel used, operating capacity, and the actual condition of each facility.

Evaluation of Inspection Results

After completing the inspection, businesses can prioritize corrective actions based on the following recommendations:

System Condition	Recommendation
Serious safety issues are identified, such as major steam leaks, water hammer, corrosion, or severely damaged equipment	Inspect and repair immediately to ensure safe operation
One or two significant energy loss points are identified	Develop a corrective action plan based on their impact and available investment budget
Three or more energy loss points remain uncontrolled	Conduct a comprehensive system assessment to determine improvement priorities
No operating data is available for O₂, CO, flue gas temperature, water quality, condensate recovery rate, or fuel consumption	There is insufficient information to accurately evaluate the operating efficiency of the boiler system

XII. Frequently Asked Questions (FAQ)

1. How can I tell if my boiler is consuming too much fuel?

Fuel consumption should be compared with steam production under the same operating conditions.
In addition, operators should monitor flue gas temperature, O₂ concentration, CO concentration, fuel quality, condensate recovery rate, boiler blowdown practices, and the actual operating load.

2. Why shouldn't boiler blowdown be performed based solely on operator experience?

If blowdown is insufficient, scale will accumulate inside the boiler and reduce heat transfer efficiency.
On the other hand, excessive blowdown wastes hot water, thermal energy, and boiler water treatment chemicals.
Therefore, boiler blowdown should be controlled based on the TDS (Total Dissolved Solids) level.

3. How do steam leaks affect boiler efficiency?

Steam leaks reduce system pressure and force the boiler to increase its operating load to compensate for the lost steam.
As a result, fuel consumption and steam production costs both increase.

4. Should the boiler be replaced when its efficiency decreases?

Not necessarily. Reduced boiler efficiency may result from fouling, scale buildup, steam leaks, damaged insulation, improper combustion, or unsuitable operating load.
The root cause should be identified before deciding whether repair, retrofit, or replacement is required.

5. Why should boiler feedwater be treated before entering the boiler?

Untreated feedwater can lead to scale formation and corrosion inside the boiler.
Both of these problems reduce heat transfer efficiency, shorten equipment life, and increase operating costs.

XIII. Conclusion

In many cases, rising steam production costs are not caused by a single issue but by multiple energy loss points occurring simultaneously throughout the boiler system.

From flue gas heat loss, boiler blowdown, steam leaks, condensate losses, inadequate insulation, boiler feedwater quality, operating load, to steam quality and deaerator performance, each factor can reduce fuel utilization efficiency if it is not properly controlled.

The key issue is not how much fuel the boiler consumes, but how much of the fuel's energy is actually converted into useful steam for production.

Businesses that effectively control these energy loss points can reduce fuel consumption, maintain stable boiler efficiency, and optimize steam production costs over the long term.

Not Every Boiler System with High Steam Costs Needs to Be Replaced. In many cases, high steam production costs are caused by several small energy losses occurring simultaneously that have not yet been measured or properly controlled.

If your boiler system is experiencing any of the following:

• Increased fuel consumption.

• High flue gas temperature. 

• Fluctuating steam pressure. 

• High make-up water consumption. 

• Rising steam production costs without a clearly identified cause. 

The technical team at DIVI Group can conduct an on-site system assessment, analyze energy loss points, and recommend improvement solutions based on investment efficiency and expected payback period.

Technical Consultation Hotline: +84 942 488 818