Rheem Water Heater Won't Light
The Short Answer: A Rheem gas tank that will not light is no flame at all — no pilot, no spark, no glow, dark port. That is a closed cock, empty LP, a control in OFF or FVIR lockout, a dead igniter, or no gas. It is not lights then dies. Electric Rheems have no light to light. If you smell gas, leave. Do not crack fittings.
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Search Intent & The Real Problem
You turned the knob. Dark. Or you waited for a tick and got silence. People bought a $12 thermocouple for a flame that never existed. Rheem, Ruud, and Richmond share Honeywell/Resideo FVIR valves — some still have a standing pilot and a piezo, many 2010-and-newer spark or use a hot-surface igniter and say do not light with a match. A cold tank with a live burner is not heating. Generic no-flame: burner not lighting. This page is Rheem, no ignition.
What other guides get wrong
They give one match-light speech for every Rheem ever built, including spark units whose jacket forbids it. They lead with “air in the line” on a tank that heated water yesterday — do not purge it. They mix three jobs: no flame, flame that will not hold, and main that drops. They paste an electric 5-flash onto a gas LED. And they poke the pilot orifice with the gas on.
Step-by-Step Troubleshooting
Step 1: Split no-flame from stay-lit, and prove it is gas
| What you see | What it actually is | Next |
|---|---|---|
| No pilot, no spark, no main, dark port | This page — no ignition | Supply, spark, lockout |
| Pilot lights, dies when you release PILOT | Thermocouple / magnet | Rheem pilot |
| Pilot holds, main never opens or drops | Thermopile / valve / rollout | Burner won’t stay lit |
| Electronic LED flashing, no standing pilot | Lockout — count flashes | Sticker on that valve |
| Click or glow, no flame, then silence | Spark/HSI with no gas, or lockout | Do not keep cycling |
| Whoosh / bang, then dark | Delayed ignition | Shut down. Not a second try. |
| Two access doors, no gas valve | Electric tank — wrong article | Rheem not heating |
| Power-vent, blower never spins | Prove circuit first | Blower |
- What to look for: Jacket lighting card. Knob with PILOT / ON / OFF and a view port = standing pilot. “Do not light with a match,” status LED, no port = electronic. Phone photo of the valve sticker and the rating plate.
- Required tools: Flashlight. No matches until that card describes them. Do not manually light an FVIR chamber.
Step 2: Cock, meter, LP, control position — without opening the pipe
- What to look for: Appliance shutoff handle parallel to the pipe (open). Control left on OFF or Vacation. Other gas appliances lighting. LP bottle empty after a cold snap; first-stage regulator a block of ice. Utility red tag. A kinked 1/2-inch flex on a high-BTU power-vent. After a storm, start at dead after a power outage — electronic and power-vent Rheems need 120 V; millivolt standing-pilot tanks do not.
- Required tools: Eyes. Manometer work is licensed (NG ~3.5–7 in. w.c. / LP ~10–11 in. w.c. at the appliance — confirm the rating plate).
Do not crack the union to “see if you have gas.” Closet odor now: closet smells like gas. Spark with a dark burner is not getting gas, not a second igniter.
Step 3: One trial — piezo, spark, or glow — cover on
- What to look for: Standing-pilot: piezo snap at the electrode, then a sharp blue pilot that wraps the thermocouple. No snap is a dead piezo, a broken lead, or a grounded ceramic. Electronic: rapid tick or an orange hot-surface bar, then main. No snap at all on a Honeywell-family valve is igniter no spark — lockout, no 120 V, cracked electrode, or a dead module. Glow with no flame is gas, not the bar. One sequence per the jacket. If it bangs, yellow-tips, or you smell fuel, shut the appliance cock — smell after lighting.
- Required tools: The lighting card. Ears and eyes at the port. Spark-only look with the appliance cock off if you only need to see whether the electrode jumps.
Repeated clicking into a dark chamber dumps unburned fuel. A hairline crack through the ceramic grounds the spark to the bracket.
Step 4: Status LED and FVIR — the sticker is law
Typical Rheem / Ruud / Richmond Honeywell/Resideo charts (the label on your valve wins — do not guess):
| LED (common atmospheric / power-vent) | Meaning | Light? |
|---|---|---|
| Short flash every few seconds | Idle / normal | Not a dead igniter |
| Heartbeat | Calling for heat | Wait for the trial |
| 3 flashes (many PV) | Pressure switch / blower | Do not fire it |
| 4 flashes | ECO / high-limit | Find the overheat; never jumper |
| 6 flashes | Failed trial for ignition | This page — spark/glow or gas |
| 7 flashes | FVIR / flammable vapor | Not an igniter wipe — 7-flash, chamber sensor |
| 9 flashes | Chamber sensor / valve fault on many stickers | 9-flash |
| Dark LED | No power to the valve, dead pile, or failed control | No status light |
- What to look for: A full cycle twice before you kill power. Lint packed in the flame-arrestor under a post-2003 tank. Gasoline, paint, solvent, a dryer dumping into the same closet. A 7-flash after painting will never spark no matter what electrode you buy. Power-vent: inducer must spin and prove before spark — pressure switch failed open.
- Required tools: Watch, phone photo of the LED and the door sticker. Vacuum around the jacket from outside. Do not pull a sealed FVIR door you cannot reseal.
A perfect igniter cannot light a burner the valve is holding closed on a safety. Richmond uses the same valve — Richmond gas valve.
Step 5: Millivolts, water in the tray, and when it is the control
- What to look for: Standing-pilot thermocouple should make ~20–30 mV once a flame exists — you cannot measure that on a dark port. Thermopile electronics live in the hundreds of millivolts; a dead pile browns the board so it never sparks. Water or a rust ring in the combustion chamber: the tank is dead; shut gas. Scorch at the control, melted harness, or a valve that never opens with supply and spark proven is the control — match gas type, FVIR, millivolt vs 120-volt power-vent. Do not thread on a “universal Rheem” from a blister pack. Tankless two-digit 11 is a different machine — Rheem code 11. Need it off? Apartment shutoff.
- Required tools: On a licensed truck: millivolt meter, manometer, leak-detection after any control swap. Not yours.
House static over ~80 psi and a dumping T&P (typical 150 psi / 210°F) will not light a burner either — that is pressure, never a cap.
When DIY Ends: Calling a Licensed Pro
Stop at gas odor, delayed-ignition bangs, a 7-flash vapor lockout, a silent power-vent, water in the tray, and any gas-valve work. You may confirm the shutoff, photograph the LED, and watch one spark or glow trial through the port. You may not jumper FVIR, match-light an electronic chamber, or loosen the flex. A licensed plumber will measure millivolts and manifold pressure, service the arrestor, and leak-test a Resideo swap. Same-day licensed ignition beats a closet full of unburned gas from a fifth click.
Frequently Asked Questions
Q: Why will my Rheem water heater not light? A: Closed gas cock, empty LP, control in OFF or FVIR lockout, a dead piezo/spark/HSI, no 120 V to an electronic or power-vent valve, or no gas at the burner. It is not automatically a thermocouple — that part only fails a flame that already existed.
Q: Can I light a Rheem water heater with a match? A: Only if the jacket lighting card describes a standing-pilot match or piezo sequence. If it says do not light with a match, it is electronic FVIR. A match bypasses spark, flame sense, and the vapor sensor. Hire a licensed plumber.
Q: The Rheem clicks but never lights. Is the igniter bad? A: Click with no spark is the igniter, boot, or module. Spark or glow with a dark burner is gas, a closed cock, or a valve that never opened. Stop cycling it. One trial after you confirm fuel, then a licensed tech.