Common Rto Burner Problems and Troubleshooting Solutions

In a Regenerative Thermal Oxidizer (RTO) system, theburner serves as the core energy source.
It is responsible not only for heating up the system during startup, but also for providing supplementary combustion when VOC concentration fluctuates or when thermal energy is insufficient. This ensures stable operation and compliant emissions.

In theory, an RTO is a stable and predictable system.
However, in real-world operation—especially during commissioning and long-term use—burner-related issues are among the most common causes of system instability and shutdowns.

From multiple project experiences, one thing becomes clear:
Most burner failures are not caused by complex equipment defects, but by small, easily overlooked details.

This article focuses on common RTO burner problems and provides a practical troubleshooting approach based on real operating conditions.

1. Ignition Failure: The Most Common but Often Misdiagnosed Issue

Ignition failure is one of the most typical problems in RTO burner operation.
In many cases, engineers tend to check the burner itself first, but experience shows that the root cause is often much simpler.

(1) Start with the Natural Gas Supply

Before moving to complex diagnostics, always verify the basics:

• Is the upstream gas valve fully open?

• Is the gas pressure stable and sufficient?

Although this may seem obvious, in several projects, ignition failure was ultimately traced back to insufficient gas supply or partially closed valves.

2. Burner System Issues: Troubleshoot in Sequence, Not by Guesswork

Once the gas supply is confirmed to be normal, the burner system should be checked step by step in a structured way.

(1) Control Mode Configuration

First, confirm that the burner is operating in remote control mode (PLC control).

If the system is left in local mode, the PLC cannot execute the full ignition sequence properly, resulting in ignition failure.
This is a very common oversight during commissioning.

(2) UV Flame Detection Problems

Although small in size, the UV flame detector plays a critical role in ignition verification.

Common issues include:

• Loose wiring leading to signal loss

• Contaminated sensor surface (dust, oil), affecting flame detection

If no flame signal is detected, the system will report ignition failure—even if ignition has actually occurred.

👉 In many cases, simply cleaning the UV sensor or tightening connections resolves the issue.

(3) Relay Contact Degradation

Relays inside the control cabinet rarely fail. Instead, they degrade over time, such as:

• Burnt contacts

• Increased contact resistance

• Unstable signal transmission

These issues can interfere with the ignition sequence but are often difficult to detect during routine inspection.

(4) Ignition Electrode Moisture Issues

In outdoor or high-humidity environments, moisture becomes a significant factor.

When moisture enters the ignition electrode:

• Insulation performance decreases

• High-voltage ignition becomes unstable or fails

This is especially common after rain or in humid climates.

(5) Spark Plug Aging

The spark plug is a consumable component.

If it has been in use for more than one year, its ignition performance will decline noticeably.

👉 Regular replacement is recommended to improve ignition reliability and reduce unexpected downtime.

(6) Burner Controller Status Analysis

Instead of blind troubleshooting, it is more efficient to check the burner controller status directly.

Focus on:

• Whether pre-purge has been completed

• Whether ignition sequence has started

• Whether flame signal has been detected

Identifying the exact step where the failure occurs helps narrow down the problem quickly.

3. Combustion Air System Issues: A Frequently Overlooked Factor

In many cases, problems are mistakenly attributed to the burner or fuel system, while the actual cause lies in the combustion air system.

Combustion Fan Inspection

Key checks include:

• Whether the air inlet is blocked

• Whether the fan pressure is within the normal range

Also check the thermal overload relay.
If it has tripped, the root cause must be identified before resetting, the issue will recur.

4. High Furnace Pressure: A Critical but Often Ignored Parameter

Furnace pressure is an important factor affecting burner stability, but it is often underestimated in practice.

When furnace pressure exceeds 4000 Pa, ignition may become difficult or fail.

Based on field experience, this typically indicates:

• Insufficient combustion air pressure

• Improper air-to-fuel ratio

• Excessive system resistance

Typical Issues at High Fan Frequency

If ignition failures frequently occur when the main fan operates at 45–50 Hz, the issue is likely not the burner itself.

Focus should be placed on system resistance, especially:

• Whether the ceramic media in the regenerative chamber is clogged

Blockage increases system resistance and disrupts combustion stability.

5. Temperature Drop After Introducing Waste Gas

A common situation during startup is:

• Ignition works normally

• But furnace temperature drops after introducing waste gas

In most cases, the cause is straightforward:

• The gas proportional valve is not fully open

• Gas supply is insufficient

This issue can usually be resolved through proper adjustment without complex analysis.

6. Communication Issues: Start with Basic Parameters

When communication failure occurs in the temperature control system, parameter settings should be checked first before replacing hardware.

Typical settings include:

• Baud rate: 9600

• Parity: Odd

• Stop bit: 1

In many cases, communication problems are caused by incorrect configuration rather than equipment failure.

Conclusion: Burner Reliability Depends on Attention to Detail

From practical experience, most RTO burner issues are not complex.
They are often the result of overlooked details.

A structured troubleshooting approach is essential:

1. Check gas supply

2. Inspect the burner system

3. Verify the combustion air system

4. Check control and communication systems

At the same time, regular maintenance—such as cleaning UV sensors, replacing spark plugs, and checking electrical connections—can prevent most issues before they impact operation.