UV vs Infrared Flame Scanners: What You Need to Know
Your UV flame scanner might be detecting a spark — not an actual flame. That's a safety problem worth understanding before it becomes a real one.
Jude breaks down the two primary flame scanner types — UV and infrared — covering which fuels each handles best, and demonstrates live on a burner how a UV scanner can falsely detect an ignition spark as a flame signal. He then shows the fix: ignition transformers specifically rated to be invisible to UV scanners.
A flame scanner that reads a spark as a flame can mask a failed ignition and allow unsafe burner operation — understanding this distinction is critical for anyone maintaining or troubleshooting gas-fired boilers.
WARE's team works with flame detection systems across a wide range of burner types and fuels — this is exactly the kind of field knowledge that comes from decades of hands-on boiler service.
Need help with flame safeguard troubleshooting or burner service? Visit wareinc.com to connect with WARE's service team.
Timestamps
0:00 - Intro: UV vs Infrared flame scanners
0:26 - When to use UV vs infrared (fuel type breakdown)
1:08 - The UV scanner spark problem explained
1:40 - Live demo: spark falsely detected as flame
2:43 - The fix: UV-rated ignition transformers
3:03 - How UV-safe transformers work (half-cycle sparking)
Related search terms
UV flame scanner boiler, infrared flame detector boiler, flame safeguard boiler troubleshooting, ignition spark UV scanner false signal, boiler burner flame detection, UV scanner ignition transformer, flame signal troubleshooting, boiler flame detector types
What is the difference between a UV and infrared flame scanner on a boiler?
UV scanners detect the blue end of the light spectrum and work best on natural gas flames. Infrared scanners detect heat radiation and are better suited for oil or dual-fuel applications where flames burn more red and yellow.
Can a UV flame scanner detect an ignition spark instead of a flame?
Yes — a standard ignition spark emits UV light, so a UV scanner can falsely read a spark as a flame signal even with no gas flowing. This is a known safety consideration in UV scanner applications.
How do you prevent a UV scanner from picking up ignition spark?
Use an ignition transformer rated for UV scanner applications — these transformers spark only during the interval when the scanner is not sampling, making the spark invisible to the detection circuit.
What happens if you replace an ignition transformer on a UV scanner system with the wrong type?
The new transformer may emit UV-visible spark, causing the flame scanner to detect ignition as a flame signal and defeating an important safety lockout function.
What fuel types work best with infrared flame scanners?
Infrared scanners are well-suited for oil, dual-fuel, and other applications where the flame burns with more red and yellow light — fuels that produce less ultraviolet radiation.
Need boiler parts, valves, gaskets, or maintenance supplies? Visit BoilerWAREhouse: https://www.boilerwarehouse.com
Learn more about WARE boiler service, rentals, training, and support: https://www.wareinc.com
Want boiler training? Learn more about Boiler University and boiler operator education through http://www.boileruniversity.com
🔔 Subscribe for weekly boiler tips and deep dive technical content.
👍Like & share to help us elevate the steam industry.
👍If you found this helpful, like, subscribe, and leave your boiler questions in the comments.
© 2026 @wareboilers. All rights reserved. Unauthorized reproduction or distribution of this content is prohibited. Ware Boilers’ videos are intended for promotional purposes only and does not constitute professional advice. Please contact our boiler professionals via https://www.wareinc.com/ with specific questions or repair needs. You should not attempt any boiler repair or modification without first consulting with a licensed contractor and the manufacturer. Ware Boilers does not warrant the accuracy, completeness, or usefulness of information available on this YouTube page. Nothing contained in or provided in any of Ware Boilers’ videos is intended to constitute advice or to serve as a substitute for a licensed contractor’s inspection or manufacturer specifications. Any reliance you place on such information is strictly at your own risk.
Jude breaks down the two primary flame scanner types — UV and infrared — covering which fuels each handles best, and demonstrates live on a burner how a UV scanner can falsely detect an ignition spark as a flame signal. He then shows the fix: ignition transformers specifically rated to be invisible to UV scanners.
A flame scanner that reads a spark as a flame can mask a failed ignition and allow unsafe burner operation — understanding this distinction is critical for anyone maintaining or troubleshooting gas-fired boilers.
WARE's team works with flame detection systems across a wide range of burner types and fuels — this is exactly the kind of field knowledge that comes from decades of hands-on boiler service.
Need help with flame safeguard troubleshooting or burner service? Visit wareinc.com to connect with WARE's service team.
Timestamps
0:00 - Intro: UV vs Infrared flame scanners
0:26 - When to use UV vs infrared (fuel type breakdown)
1:08 - The UV scanner spark problem explained
1:40 - Live demo: spark falsely detected as flame
2:43 - The fix: UV-rated ignition transformers
3:03 - How UV-safe transformers work (half-cycle sparking)
Related search terms
UV flame scanner boiler, infrared flame detector boiler, flame safeguard boiler troubleshooting, ignition spark UV scanner false signal, boiler burner flame detection, UV scanner ignition transformer, flame signal troubleshooting, boiler flame detector types
What is the difference between a UV and infrared flame scanner on a boiler?
UV scanners detect the blue end of the light spectrum and work best on natural gas flames. Infrared scanners detect heat radiation and are better suited for oil or dual-fuel applications where flames burn more red and yellow.
Can a UV flame scanner detect an ignition spark instead of a flame?
Yes — a standard ignition spark emits UV light, so a UV scanner can falsely read a spark as a flame signal even with no gas flowing. This is a known safety consideration in UV scanner applications.
How do you prevent a UV scanner from picking up ignition spark?
Use an ignition transformer rated for UV scanner applications — these transformers spark only during the interval when the scanner is not sampling, making the spark invisible to the detection circuit.
What happens if you replace an ignition transformer on a UV scanner system with the wrong type?
The new transformer may emit UV-visible spark, causing the flame scanner to detect ignition as a flame signal and defeating an important safety lockout function.
What fuel types work best with infrared flame scanners?
Infrared scanners are well-suited for oil, dual-fuel, and other applications where the flame burns with more red and yellow light — fuels that produce less ultraviolet radiation.
Need boiler parts, valves, gaskets, or maintenance supplies? Visit BoilerWAREhouse: https://www.boilerwarehouse.com
Learn more about WARE boiler service, rentals, training, and support: https://www.wareinc.com
Want boiler training? Learn more about Boiler University and boiler operator education through http://www.boileruniversity.com
🔔 Subscribe for weekly boiler tips and deep dive technical content.
👍Like & share to help us elevate the steam industry.
👍If you found this helpful, like, subscribe, and leave your boiler questions in the comments.
© 2026 @wareboilers. All rights reserved. Unauthorized reproduction or distribution of this content is prohibited. Ware Boilers’ videos are intended for promotional purposes only and does not constitute professional advice. Please contact our boiler professionals via https://www.wareinc.com/ with specific questions or repair needs. You should not attempt any boiler repair or modification without first consulting with a licensed contractor and the manufacturer. Ware Boilers does not warrant the accuracy, completeness, or usefulness of information available on this YouTube page. Nothing contained in or provided in any of Ware Boilers’ videos is intended to constitute advice or to serve as a substitute for a licensed contractor’s inspection or manufacturer specifications. Any reliance you place on such information is strictly at your own risk.
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