Responded to air quality sensor alarm activation in mechanical room. Performed comprehensive inspection of Bradford White natural gas water heater (2015 model) including combustion testing, exhaust system evaluation, gas leak detection, and examination of sealed combustion door gasket and power vent gasket. All tests confirmed proper operation with no combustion issues, gas leaks, or ventilation problems. Determined probable cause to be external wood smoke from neighboring property being drawn into fresh air intake.
