Boiler Blog | Nationwide Boiler Inc.

In industrial settings where boilers are vital to operations, safety and reliability are non-negotiable. One often overlooked component is the fuel train, or gas train, which plays a critical role in controlling fuel delivery. During budget cuts, maintenance of this system is frequently deferred—an oversight that can lead to gas leaks, combustion failures, and serious safety hazards. For facilities operating high-pressure steam systems, regular gas train maintenance is essential to prevent incidents and ensure safe, reliable performance.

Understanding the Role of the Gas Train

The gas train is a system of mechanical and electrical components that regulate fuel flow and pressure to the burner. It includes shut-off valves, regulators, pressure switches, solenoids, and piping—all working together to ensure safe fuel delivery and immediate shutdown in unsafe conditions.

Gas trains are designed to:

• Prevent unburned fuel from entering the combustion chamber
• Shut off fuel flow in the event of unsafe operating conditions
• Maintain consistent gas pressure for efficient burner operation
• Enable both manual and automatic control of fuel delivery

Even in systems equipped with modern burner management systems and interlocks, the effectiveness of these safety measures depends on proper maintenance and operator awareness.

Risks of Inadequate Maintenance

Neglecting gas train inspection and testing can lead to component failures that may not be immediately apparent but can compromise the entire combustion system. Common issues include:

• Leaking or sticking safety valves
• Inaccurate or failed pressure switches
• Improperly functioning regulators
• Worn or bypassed interlocks
• Electrical wiring faults

In many documented incidents, failures were not due to a lack of safety devices, but rather a lack of routine testing and operator training. Preventive maintenance is essential to avoid these scenarios.

Best Practices for Gas Train Safety

Implementing a structured maintenance and safety program can mitigate risks and improve system reliability. The following practices are strongly recommended:

1. Staff Training and Competency

Operators must be trained not only in basic boiler operation but also in combustion safety and hazard recognition. Training programs should include hands-on system reviews, mock upset drills, and instruction on emergency response procedures. Even when maintenance is outsourced, in-house personnel should have a fundamental understanding of the systems they oversee.

2. Written Startup and Shutdown Procedures

Many combustion incidents occur during equipment startup or shutdown. Standardized, clearly written procedures ensure consistency across shifts and personnel. These procedures should include purge verification, valve testing, and system readiness checks.

3. Routine Testing and Documentation

Facilities should establish a regular schedule for testing gas train components, including:

• Valve leak and tightness testing
• Functional testing of pressure switches and interlocks
• Flame safeguard system checks
• Compliance with applicable NFPA, ASME, and local code requirements

Documenting all tests and inspections ensures traceability and supports compliance efforts.

4. Third-Party Equipment Reviews

When acquiring new equipment or undergoing significant upgrades, a third-party review can help verify compliance, confirm correct installation, and identify design deficiencies. This is especially important when retrofitting legacy systems with modern controls or safety components.

5. Proactive Equipment Upgrades

Waiting for failure is not a viable safety strategy. Facilities should establish a timeline for replacing aging components and upgrading outdated systems. Modern PLC-based burner management systems and digital flame safeguards offer improved diagnostics, safety, and reliability.

Building a Culture of Safety

The safe operation of permanent boilers, rental boilers, and boiler combustion equipment depends not just on hardware, but on the culture and procedures that support it. Gas train maintenance should be treated as a critical operational task—not an afterthought. Investing in training, testing, and system upgrades enhances reliability, reduces unplanned downtime, and most importantly, protects personnel.

This blog post was originally published in September 2011 and has been updated to reflect current best practices, safety standards, and advancements in gas train maintenance.

Companies require rental equipment for several reasons. By understanding the rental process and following the guidelines below, it is possible that the result will be both cost-effective and technically successful.

Steam Requirements - Up front planning is the most important stage when renting equipment. First, the maximum potential steam load needed must be calculated. Your steam requirement is expressed in either boiler horsepower (hp) or lb/hr (one boiler horsepower is equal to 34.5 lb/hr steam at 212°F).

Accessible Location - A location must be selected that is easily accessible for the delivery and setting of heavy machinery and one which has easy access to the building or equipment in which the steam will be required.

Utility Connections & Supply - Fuel, water and electric power connections must be easy to access and are of sufficient size to meet the needs of the rental unit. Typically, rental boilers fire natural gas, No. 2 oil, or heated No. 6 fuel. It is also important to make sure that there is sufficient fuel capacity to supply any existing units and a temporary boiler.

Equipment Supplier - When evaluating a supplier of rental equipment it is important to know if the company is a full-time, dedicated rental company with the experience, equipment and capabilities you require. In addition, the location of the company's equipment is important, helping to minimize transportation costs and travel time. It is also important to determine if the company provides start-up and installation services.
Here at Nationwide, we have boilers located throughout the United States and our service department is available 24 hours a day for technical support.

Reputable rental companies will provide complete drawings and equipment specifications in considerable detail. Such items include the total capacity and operating characteristics of the boiler, water treatment needs and requirements, emissions requirements, weather protection, performance testing, and ASME code requirements.

Proposal Evaluation - When evaluating a proposal, normal factors including payment terms, change-of-scope clauses, liability coverage, and transportation costs need to be addressed. A well written proposal should address the rate and term on the rental unit, freight costs, time and travel charges for technicians, and should specify appropriate responsibility for installation and removal costs. You should also get the warranty statement for the rental equipment.

Operating Permits - Before installation of the equipment can occur, it is necessary to arrange for any operating permits required from regulatory agencies. This includes special permits that may be required in those areas where emission limits are strictly controlled. Areas in California including the San Joaquin Valley and the South Coast require sub-10 ppm NOx requirements.

Nationwide Boiler took the lead in equipping our units with Low NOx burners and SCR systems (the CataStak). Users facing 5 ppm NOx can rest assure that we have an immediate solution.

Maintenance - To ensure continuous, safe, and trouble free performance of the unit, there are a number of regular checks and maintenance tasks which must be performed. It is important that a log sheet be kept on site for the recording of every routine check and maintenance items completed. Daily checks include an examination of all safety devices, followed by an inspection of the low-water cutoff during every shift. The entire system should also be checked for leaks and corrected immediately. The flame pattern of the burner must also be inspected to make sure the combustion devices are working efficiently. Moreover, proper boiler performance is highly dependent on following the proper feedwater treatment and correct blowdown techniques. Failure to maintain proper water chemistry is a major cause of damage to rental boilers and the single biggest rehabilitation expense.

Return Shipment - Lastly, there are certain steps that must be taken to ensure safe return of a unit to the rental company's facility. It is the responsibility of the user to have plant or local boiler shop personnel disconnect equipment after use, which includes draining and flushing all boiler lines with clean water to help minimize any chance of corrosion. A final check of the condition of the boiler should be properly documented, recorded and sent to the rental company once the equipment is shipped.

As long as you plan in advance, budget accordingly, verify connection sizes, address permitting issues, properly train operators, frequently monitor the feedwater quality, and take responsibility in maintaining the equipment once it is installed, you can be confident that the risks associated with renting equipment will be minimized and that your project will be a success.