Water heater gas burner no hot water — gas burner

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

1. Check 1

   From a safe position outside the suspected odor area, note whether there is a rotten-egg gas odor, hissing, a carbon-monoxide alarm, smoke, or anyone with headache, dizziness, nausea, confusion, or unusual weakness; do not operate a switch, phone, lighter, or appliance control in the odor area.

   Expected result: There is no gas odor, hissing, CO alarm, smoke, or illness, or one of those warning signs is present.

   Next step: If any warning sign is present, leave the building or odor area, keep others away, and call 911 or the gas utility from a safe location. If none is present, continue without opening the heater or disturbing gas piping.

   Stop if: Stop immediately for gas odor, hissing, a CO alarm, smoke, or symptoms that could be CO exposure; do not relight or re-enter until the responsible emergency or gas professionals say it is safe.

   Why this matters

   Why: A warning sign changes this from a hot-water diagnosis to an immediate gas or combustion-safety response; an absence of warning signs only permits the limited visual checks below.

2. Check 2

   Read the heater's visible label and look through the intended viewport or at the exterior status indicator from ordinary standing access; record whether a pilot or ignition indication is present and record any displayed pattern without removing a door or panel.

   Expected result: The pilot or ignition indication is absent, present and steady, repeatedly attempting to start, or showing a pattern that the model manual identifies as a fault; the viewport is intact or damaged/missing.

   Next step: Use the exact model manual to interpret the indicator. If there is no indication, an unexplained code, or a damaged/missing viewport, photograph the label and arrange qualified service instead of opening the burner compartment.

   Stop if: Do not remove the burner door, reach into the combustion chamber, jumper a sensor, or interpret an unfamiliar flash pattern as permission to keep operating the heater.

   Why this matters

   Why: No indication points toward the ignition, gas-control, or flame-sensing path, while a present pilot only establishes the small ignition flame and does not prove that the main burner is heating the tank. A damaged or missing viewport is a stop condition.

3. Check 3

   Only when there is no gas odor, the viewport is intact, and the installed label or manual explicitly provides a homeowner relighting sequence, follow that sequence exactly; for a traditional pilot, the A. O. Smith guide describes turning the gas control off and waiting at least 10 minutes before attempting the model-directed pilot position and ignition, but the unit's own instructions take precedence.

   Expected result: The pilot lights and remains lit after the control is released, the status indication returns to the normal pattern described by the manual, or the pilot will not light/stay lit after the permitted attempts.

   Next step: If the model-directed sequence succeeds, continue to the safe burner observation and allow the unit to heat according to the manual. If it fails, stop, leave the gas control in the safe state specified by the manual, and request qualified gas-appliance service.

   Stop if: Do not relight if gas is smelled, the viewport is damaged, the unit has soot or abnormal flame, the manual is unavailable, or the pilot repeatedly fails; do not use a hand flame where the unit specifies electronic ignition.

   Why this matters

   Why: A stable pilot or normal ignition indication makes a temporary ignition outage plausible, but a pilot that repeatedly goes out can involve the flame-sensing device, draft, combustion air, gas pressure, or control valve. Failure after the manual's permitted attempts is not a cue to keep trying.

4. Check 4

   With all covers and doors in their normal installed position, create an ordinary hot-water demand as the manual describes and look only through the intended viewing window; do not touch the burner or gas fittings while observing whether the main burner starts and remains on.

   Expected result: The main burner starts and continues heating, starts then drops out, or never starts even though the pilot or ignition indication is present.

   Next step: Record the pattern and the exact model information. If the burner does not start or repeatedly drops out, stop use and arrange qualified service; if it runs normally, continue by comparing hot-water outlets and wait only for the model's documented heating period.

   Stop if: Stop for a yellow or lazy flame, flame rollout, soot, unusual noise, smoke, smell, repeated dropout, or any need to remove the burner door or adjust gas components.

   Why this matters

   Why: A burner that never responds with a stable pilot makes the control, thermostat, gas-supply, or flame-sensing path more likely than a water-outlet fault. A burner that drops out repeatedly can indicate a safety, combustion, or control problem. A normal burner response does not prove that venting or water-side components are healthy.

5. Check 5

   From floor level and without climbing, disassembly, or contact with hot surfaces, inspect only the visible vent termination and combustion-air openings for an obvious leaf, snow, lint, storage item, or other obstruction; do not reach into the vent or burner area.

   Expected result: The visible path is clear, or an obstruction, soot/discoloration, damaged vent, or restricted opening is visible.

   Next step: Keep people away and arrange qualified service for any obstruction that is not removable without touching the appliance, for soot/discoloration, damaged venting, or a recurring shutdown. Do not resume operation based only on a clear exterior view.

   Stop if: Do not remove vent sections, open the combustion chamber, brush the burner, adjust draft, or continue operation when combustion or venting appears abnormal.

   Why this matters

   Why: A blockage or soot/discoloration can make combustion and venting unsafe and can contribute to pilot dropout or burner shutdown. A clear visible path does not certify the flue, draft, combustion air, or internal burner condition.

6. Check 6

   After the heater has had the model's documented heating period and while keeping the test brief, compare hot-water temperature and flow at two fixtures; compare each with its cold-water flow and note whether only one outlet is affected or every hot outlet is cold.

   Expected result: One fixture is cold while another is hot, hot-water flow is absent or much weaker than cold flow, or all hot outlets are cold despite a normal burner response.

   Next step: Use the outlet pattern, burner pattern, model, and time since the last hot-water draw when requesting service. Do not increase the temperature setting beyond the label or bypass a mixing or safety control to force hot water.

   Stop if: Stop for scalding temperature, a leak, water damage, unstable temperature, or any need to open a faucet cartridge, valve, wall, tank, or gas appliance.

   Why this matters

   Why: A single cold fixture makes a local faucet, mixing, or plumbing restriction more likely. All outlets cold with no burner response supports a heater-side ignition/control diagnosis; all outlets cold with a normal burner response shifts attention to recovery, thermostat, tank, outlet plumbing, or a mixing component.