A. O. Smith water heater gas pilot keeps going out: What to Check and What to Do Next

Use only checks that match the exact appliance or system and its official guide.

1. Check 1

   Before touching the controls, look and smell from a safe position for a gas odor, smoke, soot, flame outside its intended viewing area, or an unusual burning or exhaust smell; do not create a spark or operate an electrical switch to investigate.

   Expected result: There is no gas odor, smoke, soot, abnormal flame, or unusual exhaust concern, or one of those hazards is present.

   Next step: If any hazard is present, leave the area when necessary, avoid ignition sources, and contact the gas supplier or emergency service from a safe location. Otherwise continue with the model-specific identification check.

   Stop if: Do not attempt to light the pilot when gas is smelled or when smoke, soot, uncontrolled flame, or an exhaust concern is present.

   Why this matters

   Why: A clear area permits only the ordinary label-directed checks below. Any gas or combustion warning is a stop-use condition, not a relight branch.

2. Check 2

   Read the rating label and instruction panel from ordinary safe access and note the model, gas type shown on the label, control style, igniter style, status-light behavior, and any displayed pattern; do not remove the burner, manifold, wiring, or control cover.

   Expected result: The heater has a traditional standing pilot, an electronic or direct-spark sequence, or an unclear system; the manual and label are available or missing.

   Next step: Use the exact A. O. Smith manual for the recorded model. If the system cannot be identified, stop and provide the label information to qualified service rather than guessing at the control sequence.

   Stop if: Do not use a match or lighter, move gas controls, or open access covers unless the exact model instructions expressly require and permit that step and the area remains free of hazards.

   Why this matters

   Why: The relight and status indications are model-dependent. A missing manual or an unclear ignition system removes the basis for a safe generic sequence.

3. Check 3

   From the normal viewing position, record when the pilot disappears: immediately when the control is released, after the burner starts, after the heater has run for a while, or before a flame can be established; do not hold the control open to extend the test.

   Expected result: The flame dies on release, dies during burner operation, goes out after a repeatable interval, or never lights; record any status-light change at the same time.

   Next step: Use this timing to select the matching branch below and give the record to the technician. Do not infer that replacing a thermocouple will correct a draft, vent, or airflow problem.

   Stop if: Stop immediately if the flame lifts, rolls out, changes abnormally, produces soot, or cannot be viewed safely through the intended opening.

   Why this matters

   Why: Dropout on release makes the thermocouple or thermopile, pilot flame quality, connection, or gas control more likely. Dropout during operation makes a draft, combustion-air, vent, flame-arrestor, thermal-switch, or gas-supply issue more important. No flame can also involve ignition or a blocked pilot route.

4. Check 4

   Only if there is no gas odor and the exact model label permits a homeowner relight, turn the gas control to the required Off position, wait at least 10 minutes, and follow that label's Pilot and igniter sequence once; do not improvise a different sequence or continue repeated attempts.

   Expected result: The pilot lights and remains lit after the control is released, the pilot lights but goes out on release, the pilot never lights, or the model status light does not show the expected result.

   Next step: If the pilot fails, goes out again, or the status indication is not the manual's expected result, turn the control Off and arrange qualified service. If it stays lit, observe only for the normal sequence and stop if the outage returns.

   Stop if: Do not relight more than the exact manual allows, hold the control open, bypass a safety device, or keep operating the heater after a repeat outage.

   Why this matters

   Why: A pilot that remains lit after the label-directed attempt makes a temporary outage or control-state issue possible, but recurrence is not resolved. Failure on release supports a flame-sensing, pilot, connection, or control problem; no flame or an unexpected status pattern needs model-specific service diagnosis.

5. Check 5

   With the heater Off and cool, inspect only the accessible area around the combustion-air openings, the base-ring or flame-arrestor exterior if the model manual identifies it, and the visible vent termination; remove only loose household debris that the exact manual says a homeowner may remove, without disassembly.

   Expected result: The air path and vent termination are clear, lint or dust is present, the flame-arrestor area is discolored, the vent is restricted, or the inspection cannot be completed without opening the heater.

   Next step: Keep the heater Off and request qualified gas-appliance service for a restricted vent, discoloration, repeated dropout, or any inspection requiring a cover or burner access. Do not block air openings or relocate stored items into the required clearance.

   Stop if: Do not remove the flame arrestor, alter venting, defeat a thermal switch, use compressed air into the burner, or operate the heater with a restricted or discolored combustion path.

   Why this matters

   Why: A blocked air path, draft, vent restriction, or dirty flame-arrestor area can extinguish the pilot or activate protection. Discoloration or a restricted vent can indicate an unsafe combustion condition rather than routine dirt.

6. Check 6

   Record the model and fuel label, outage timing, status-light pattern, number of permitted relight attempts, visible pilot or burner behavior, recent changes near the heater, and whether other gas appliances are operating normally; take exterior photos only from a safe position.

   Expected result: The record shows an isolated pilot issue, a whole-gas-supply symptom, a repeatable status pattern, an airflow or vent concern, or insufficient information to distinguish them.

   Next step: Give the complete record to a qualified plumbing or gas-appliance technician and the gas supplier when the symptom affects more than this heater. Leave the heater Off until the repeat outage has been assessed.

   Stop if: Do not test gas pressure, electrical output, live wiring, the gas control, or vent draft as a homeowner check.

   Why this matters

   Why: An isolated pilot issue can involve the pilot assembly, flame-sensing part, wiring, or gas control. A broader gas symptom can involve supply pressure or the gas supplier. A repeatable status pattern can narrow the model-specific diagnosis, but it is not a universal code.