Common RTO Alarms Solutions & Aftermarket Service Options

Regenerative Thermal Oxidizers are generally very reliable air pollution control, capture and compliance equipment.  There are common reasons why you may get alarms during operations due to process changes, deferred maintenance and or unforeseen events or conditions.

We have put together a list of common issues that equipment owners often experience, the possible causes and solutions that may or may not require aftermarket repair or services.

If you would like to use this guide as a resource or share with your plant manager, please call us at (562)997-0233 email our SERVICE DEPARTMENT with your request and we will gladly email it to you.

If you are unable to find a solution, please feel free to call Ship & Shore and ask for our service department to speak with our qualified service technician at (562)997-0233 immediately to avoid costly shutdowns or damage.

Alarm description Possible causes Possible Solutions/ Corrective actions

 

Thermocouple broken wire fault
  • Loose thermocouple wire
  • Damaged thermocouple
  • Damaged thermocouple wire

 

  • Check the thermocouple wires & connections.
  •  Use the second thermocouple element
  •  Use a new thermocouple

 

 

Thermocouple alarm (high temp)
  • High temperature from the process
  • Inaccurate reading from the thermocouple
  • Loose thermocouple wire
  • Damaged thermocouple
  • Damaged thermocouple wire

 

  • Check the process for any possible changes
  • Check the accuracy of the thermocouple
  • Check the thermocouple wires & connections.
  • Use the second thermocouple element
  • Use a new thermocouple

 

 

High Temperature Limit Controller Fault (manual reset)
  • RTO chamber temperature is more than 1800F
  • Check the process for any possible changes
  • Check the thermocouple
  • Check the air flows to the units
  • Check the capacity of the unit. RTO may be overloaded.
  • Check the status of the hot by pass ( if applicable)
  • Check the alarm set point on the temperature limit controller
  • Make sure that the alarm has been rest manually on the controller.

 

Low temperature warning alarm
  • RTO chamber temperature is less than 1425F when RTO  is online
  • Check the process for any possible changes
  • Check the RTO ready temperature set point on the HMI screen
  • Check the RTO ready temperature  timer set point on the HMI screen
  • Check the RTO differential temperature set point on the HMI screen
  • Check the RTO burner PID loop

 

High hopper A temperature fault

 

High hopper B temperature fault

  • Hopper temperature is more than 425F.
  • Check  the thermocouples
  • Check air flows to the unit
  • Check RTO high hopper temperature set point on the HMI screen
  • Check the poppet cycle time on the HMI screen
  • Check the sealing on the unit
  • Check VFD frequency

 

High Stack temperature
  • Stack temperature is more than 450F.
  • Check  the thermocouples
  • Check air flows to the unit
  • Check RTO high stack temperature set point on the HMI screen
  • Check the poppet cycle time on the HMI screen
  • Check the sealing on the unit
  • Check VFD frequency

 

Poppet  extension proximity switch fault

 

Poppet retraction proximity switch fault

  • PLC cannot confirm the position of the poppet
  • Check the field wiring for any possible loose wire
  • Check the proximity/reed switches for any possible damages
  • Check the poppet fault timer set point on the HMI
  • Check the poppet actuators
  • Check the poppet  travel speed

 

Low compressed air fault
  •  Low compressed air pressure from the compressor
  • Set point on the compressed air pressure switch on the RTO

 

  • Adjust compressed air pressure switch
  • Check air filter
  • Check air line for possible debris
  •  Check the wiring for any possible loose wire
  •  Check the air compressor

 

Hydraulic unit temperature fault
  •  High temperature on the hydraulic unit
  • Check for any possible leaking on the unit
  • Check the wiring for any possible loose wire

 

Hydraulic fluid level fault
  •  Low hydraulic fluid level
Hydraulic fluid pressure fault
  •  Low or high hydraulic fluid pressure
Combustion blower air flow fault
  • Low combustion air pressure
 

  • Check the combustion blower rotation.
  • Check the combustion blower motor starter. If it is tripped, it should be reset manually.
  • Check the combustion line for possible debris
  • Check the combustion air pressure differential switch set point
  • Check the wiring for any possible loose wire
  • Check the combustion blower air flow fault timer set point on the HMI

 

Main  supply fan air flow switch fault
  •  Low air pressure to the unit
  • Check the main blower rotation.
  • Check the main blower motor starter, soft starter or VFD.
  • Check the RTO inlet for any possible debris
  • Check the main supply fan air pressure differential switch set point
  •  Check the wiring for any possible loose wire
  • Check the main supply fan  air flow fault timer set point on the HMI

 

VFD Fault (manual reset)
  • VFD fault signal from the VFD panel
  •  Check the alarm history from the VFD panel.

 

Clear path damper fault

 

3-Way Damper Fault

 

Fresh air damper fault

 

Process isolation damper fault

 

Diverters fault

 

Puff damper fault

 

Hot by pass fault

 

Secondary fresh air damper fault

 

 

  • PLC cannot confirm the position of the damper
  • Check the wiring for any possible loose wire
  • Check the proximity, reed  or auxiliary switches
  • Check the dampers actuator
  • Check the damper fault  timer set point on the HMI
  • Check the 4-20ma signal on the actuator ( if applicable)
Low Gas Pressure Switch Fault (manual reset)
  •  Not enough natural gas pressure
  • Check the supplied gas
  • Check the set point on the low gas pressure switch
  • Check the wiring for any possible loose wire
  • Make sure that the switch has been reset manually

 

High gas pressure switch fault
  • Excessive natural gas pressure
  • Check the supplied gas
  • Check the set point on the low gas pressure switch
  • Check the wiring for any possible loose wire
  • Make sure that the switch has been reset manually (Canada only)

 

No Flame Detected or Veri-Flame Fault
  • Burner monitoring system cannot confirm that flame exists
  • Clean the UV scanner
  • Check the wiring for any possible loose wire
  • Check the ignitor
  • Check the air/gas damper
  • Check the ignition transformer
  • Monitor the DC voltage at the burner monitoring system
  • Consider burner fine tuning or tuning
Gas POC switch Fault
  • PLC cannot confirm that gas safety shut off valve is closed
  • Check the safety shut off valve
  • Check the indicator
  • Check the wiring for any possible loose wire
  • Check the gas POC (proof of closure) fault timer on the HMI
Low fire switch fault PLC cannot confirm that burner is at low fire position
  • Check the low fire switch on the burner or auxiliary switch on the burner actuator
  • Check the burner actuator
  • Check the 4-20ma signal on the burner actuator
  • Check the mechanical linkage
  • Check the wiring for any possible loose wire
  • Check the burner low fire switch fault timer on the HMI
Low PLC battery PLC battery voltage is low (Mitsubishi only)
  • Consider changing the PLC battery
Low ambient temperature Ambient temperature is below gas train temperature rating
  •  N/A