Check the exact meaning of the light
Record the model, serial number, control identification, and visible light pattern. Ask the technician to compare it with that model's official status table.
A. O. Smith's January 2015 ultra-low-NOx FVIR manual provides separate status-code and burner-flame guidance. Its flame instructions apply to the covered equipment, not every gas heater. A. O. Smith model-specific guidance.
Do not judge the flame from a universal online color rule. A photo can document a change; it cannot establish gas pressure, draft, or combustion performance.
Describe what changed
From a safe position, tell the provider when you first noticed it, whether it happens throughout heating, and whether there is unusual noise, soot, odor, or nearby work.
Do not remove sealed burner doors, reach into the compartment, or run a match-based vent test yourself. If inspection requires opening equipment, leave it to the technician.
Ask whether the heater should remain off pending inspection and how to follow its actual shutdown instructions safely. Do not continue operating it simply to collect more video.
Request a supported conclusion
The technician should assess the flame and relevant fuel, vent, air-supply, and control conditions using the applicable service procedure. Request findings, readings where appropriate, and any limitation on the inspection.
If a repair or replacement is recommended, ask what condition supports it and how safe operation will be verified afterward. A normal light alone should not be the explanation for dismissing a changed flame.
Your next step is to arrange qualified combustion review with the model information and existing observations. Ask for the finding and operating direction in writing, rather than treating the status light as clearance.