Reading the gas control status LED (Rheem, A.O. Smith/State, Bradford White)

Thermopile-powered gas controls report their state by counting blinks, then pausing. Reading the code correctly tells you whether the problem is the pilot, low thermopile power, overheating, a sensor or the control itself. Only codes confirmed by two sources are listed; everything gas-side is diagnosed here and referred to a licensed gas technician.

Cross-checked ~15 min easyBrands: Rheem, Ruud, Richmond, A.O. Smith, State, Bradford White

Before you start

GAS: if you smell gas, do not touch switches or flames; leave and call the gas utility or 911
Diagnosis only: gas control, pilot, thermopile, burner, thermal switch and venting repairs go to a licensed plumber/gas technician
Do not relight repeatedly; codes for overheating or control failure mean shut the gas off and refer

Diagnostic steps

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

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