American Water Heater Pilot Won't Stay Lit
The Short Answer: An American-branded standing-pilot tank that lights while you hold the knob and dies when you let go is a thermocouple that is not proving — dirty, bent, loose, or dead. A pilot that will not appear is gas, a clogged orifice, or a packed FVIR screen. American is AO Smith / State hardware. If you smell gas, leave. Do not needle a live orifice.
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Search Intent & The Real Problem
You held PILOT until your thumb cramped. The flame was there. You released. Dark. That millivolt circuit is a thermocouple (~20–30 mV) or, on some millivolt American valves, a thermopile (hundreds of millivolts) proving flame to the gas control. American Water Heater Company is AO Smith’s mid-tier line — same burners as State Select, Reliance, Craftmaster, and many Whirlpool builds. Wrong door gasket, wrong thermocouple, CO path. Full hub: American troubleshooting. Parent: AO Smith. Same-family pilots: State Select, Whirlpool. Generic stay-lit: will not stay lit.
Some electronic Americans have no standing pilot. If the jacket says do not light with a match, believe it. Relighting a spark unit is how you fill a closet with gas — do not match-light electronic.
What other guides get wrong
They copy a generic “clean the pilot with a needle” list onto an FVIR American. Pulling that burner without reseating the door gasket is a CO path. They treat every American as a standing pilot, including Intelli-Vent and power-vent units that say do not light with a match. They sandpaper a thermopile and call it a thermocouple. They paste Rheem 5-flash onto the valve — 5 flashes is often a Rheem electric chart. And they still describe cracking the union. Do not purge the line.
Step-by-Step Troubleshooting
Step 1: Confirm you actually have a standing pilot
| What you have | “Pilot will not stay lit” means |
|---|---|
| Knob PILOT / ON / OFF, view port, lighting sticker | Standing pilot — this page |
| Status LED on a Honeywell / Resideo valve, still a view-port pilot | Standing pilot with diagnostics — count flashes on that sticker |
| No view port, spark module, “do not light with a match” | Electronic. Not a thermocouple job |
| Power-vent American with a blower | 120 V, pressure switch — do not fire a silent blower |
| Polaris stainless, sealed burner | Wrong machine — Polaris |
| Two electric doors, no gas valve | No pilot. Wrong article |
- What to look for: Rating plate (often G-prefix, American Water Heater Co., Johnson City or Ashland City). Jacket lighting sticker. Gas-valve brand. Phone photo of all three.
- Required tools: Flashlight, phone camera.
If the sticker says wait five minutes after shutdown, wait five minutes. Electronic no-heat: status light not blinking, electronic fault, AO Smith 3 blinks. Need it off? Shutoff.
Step 2: Gas cock, then one lighting attempt
- What to look for: Appliance shutoff handle parallel to the pipe (open). LP tank not empty. Other gas appliances lighting. Follow the jacket: OFF, wait, PILOT, hold, piezo or match only if that card allows it, hold 30–60 seconds after the flame appears, release, then ON.
- Required tools: The jacket instructions. A long lighter only if the sticker says so.
If it never appears, stop. A clogged pilot orifice, a closed cock, or a dead piezo is not a tenth match. No spark: piezo will not spark. A bang or whoosh is delayed ignition — shut the appliance cock — loud bang. Odor during a relight: smell gas after lighting — leave.
Step 3: It lights, then dies when you let go
| Clue | Cause |
|---|---|
| Flame present, dies on release | Thermocouple not proving (dirty, bent out of flame, failed, loose nut) |
| Tiny yellow cap, will not wrap the tip | Pilot orifice or low gas pressure |
| Lights, runs, dies minutes later | FVIR screen, thermopile sag, draft, ECO / overheat |
| Dies when you turn the temperature dial | Dial-out — valve or thermopile under load |
| Pilot holds, main burner drops | Not this page — burner will not stay lit |
| Water dripping onto the flame | Drip on the pilot — leak, not a thermocouple |
- What to look for: Eyes at the view port. Thermocouple tip in the flame, nut snug plus about a quarter turn at the valve. Gorilla-tight cracks the fitting and still will not latch. Thermocouple ~20–30 mV open-circuit. Thermopile hundreds of millivolts, sagging when the main opens.
- Required tools: The view port. A millivolt meter only if you are qualified.
A thermocouple you just replaced that still will not hold is this failure — wrong millivolt part, bad valve, or a draft. Same-family swap path: Honeywell thermocouple. Cold-closet American in a garage: pilot out in cold weather. Rheem-built cousins use a different burner door — Rheem pilot. GE-stamped tanks are a different OEM mix — GE pilot.
Step 4: FVIR screen, combustion air, and vapor lockout — look, do not rebuild
- What to look for: Dust mat under the tank, a closet with no combustion air, paint over the arrestor, a lawn mower or gasoline can in the same garage (flammable-vapor sensor trip). Lint-packed screen so the pilot cannot get air. Chamber / FVIR lockout is a licensed call — chamber sensor.
- Required tools: Flashlight at the base. Vacuum around the jacket from outside. Do not unscrew the sealed burner door unless you are licensed to reseat that gasket.
A tripped vapor sensor on some Honeywell / Resideo controls will not let the pilot stay. That is a control replacement after you find why vapors were there — not a reset loop. Richmond-family valves: Richmond gas valve.
Step 5: When “air in the line” is the excuse, and when the valve is done
- What to look for: New flex, new tank, or a meter relight in the last 24 hours. Delayed ignition. Pilot that will not start after a swap. LED flash codes on the valve after one correct lighting attempt. Water in the tray or a rust ring — shut the gas; keep firing that and you have a carbon monoxide problem. One slow flash with hot water on many AO Smith-family valves is normal — white light.
- Required tools: None on the fittings. Manometer work is licensed: NG ~3.5–7 in. w.c. / LP ~10–11 in. w.c. — confirm the rating plate.
Air after a reconnection is real. Cracking the union in a closet is how garages fill. Closet odor with no relight in progress: closet smells like gas. Power-vent: silent inducer means do not fire — blower not working.
When DIY Ends: Calling a Licensed Pro
You may confirm the shutoff, follow the jacket lighting sticker once, and keep the area around the FVIR screen clean. Stop at gas odor, delayed ignition, a valve that will not latch after one correct attempt, a melted burner door, water in the combustion chamber, and any electronic-ignition or power-vent American. Thermocouple replacement that requires pulling an FVIR burner, gas-valve swap, and manifold-pressure checks are licensed. Do not hold the knob in to keep a dead thermocouple “working.” AO Smith-family part numbers help a tech; they do not make this a hardware-store science project.
Frequently Asked Questions
Q: Why will my American water heater pilot not stay lit? A: The thermocouple is not proving flame, the pilot orifice is weak, the FVIR screen is packed, or the gas valve is failing. If you smell gas, do not keep relighting. Confirm the unit actually has a standing pilot first.
Q: How long should I hold the American pilot button? A: Follow the jacket sticker — typically 30–60 seconds after the flame appears. Holding it for five minutes does not fix a dead thermocouple or a vapor lockout.
Q: Is an American pilot the same as AO Smith or State Select? A: Same parent, same millivolt hardware family. Use AO Smith / State parts that match millivolt vs electronic, NG vs LP, and the FVIR plug. Polaris is the outlier — different burner, different page.