Rheem Water Heater Pilot Light Won't Stay Lit
On this page (6 sections)
The Short Answer: Current Rheem atmospheric gas water heaters use a pilot that heats a thermopile, which powers the gas control. If the pilot goes out, the usual causes are a weak or dirty pilot flame, a clogged air intake, drafts, or a tripped safety such as the flammable-vapor or chamber sensor. The status light helps narrow it down. Relight once following the label; if it keeps going out, call a technician.
Use the status light first
Rheem’s Use & Care manual (opens in a new tab) for its atmospheric gas tanks explains the light on the gas control. A normal heater flashes blue once every few seconds. When the pilot is out, the light is off, or briefly solid while the thermopile cools.
| What the light does | What Rheem says it means | What it suggests |
|---|---|---|
| Off | Control off, pilot not lit, or not enough millivolts | Pilot out; relight per the label |
| Solid | Pilot recently went out and the thermopile is cooling | Wait before relighting |
| 2 red flashes | Low thermopile voltage, pilot still lit | Weak pilot or failing thermopile |
| 4 red flashes | High water temperature limit tripped | Overheat; needs service |
| 9 red flashes | Chamber sensor failure | Combustion air or flame problem; see Rheem 9 flashes |
Older Rheem heaters with a plain OFF/PILOT/ON knob and no status light use a thermocouple instead. The causes below still apply.
Common reasons the pilot goes out
- Dirty or clogged air intake. Rheem’s flammable-vapor-resistant heaters draw combustion air through a screen near the base. Lint, dust, and pet hair there starve the pilot.
- Weak pilot flame. A partly clogged pilot orifice gives a small or yellow flame that doesn’t heat the thermopile enough. The 2-flash code often shows up first.
- Drafts and venting. A pilot that goes out when a fan, dryer, or furnace starts, or on windy days, points to drafts or a venting problem. See pilot light goes out in cold weather.
- Flammable vapors. Gasoline, paint, or solvent fumes near the heater can trip the flammable-vapor protection.
- A failing thermopile or gas control. If the flame is good and the pilot still won’t hold, one of these is likely.
What you can check safely
- Confirm the gas valve on the supply pipe is open and other gas appliances work. On propane, check the tank.
- Note the status light pattern before doing anything else.
- Clear dust and lint from the floor around the heater and from the outside of the air-intake screen, and keep stored items away from it.
- Move fuel cans and solvents out of the room.
- Relight once using the instructions on the heater’s label, waiting the time the label specifies.
What the technician will check
A Rheem-trained technician will measure thermopile output with the pilot lit, check the pilot flame and orifice, and inspect the combustion chamber and flame arrestor for blockage. They will check the chamber sensor and flammable-vapor protection, look at venting and draft, and confirm gas pressure. The sealed burner door on these heaters must be refitted correctly, so opening it is service work, not an owner step.
Repair or replace
Pilot assemblies, thermopiles, and gas controls are repairable on a sound tank. A flammable-vapor or chamber-sensor trip needs its cause found and fixed, which may mean cleaning the arrestor or replacing the sensor. A leaking tank, or water and rust in the burner area, means replacement.
Related: why won’t my gas water heater stay lit and Rheem water heater won’t light.
Frequently Asked Questions
Q: How long should I wait before relighting a Rheem pilot? A: Follow the wait time on your heater’s lighting label. If the status light is solid, the thermopile is still cooling and the control won’t relight yet.
Q: Does my Rheem use a thermocouple? A: Current Rheem atmospheric models with a status light use a thermopile. Older models with no status light typically use a thermocouple. The two are not interchangeable.
Q: The pilot stays lit but I get 2 red flashes. Is that a problem? A: Rheem lists 2 flashes as low thermopile voltage. The heater may keep working for a while, but it usually means the pilot flame or thermopile needs attention before it stops completely.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- Rheem: gas water heater Use & Care manual AP23698 (status light codes) (opens in a new tab)Rheem atmospheric natural gas and LP storage heaters (29 to 55 gallons) covered by AP23698.
- Rheem: owner help and support (opens in a new tab)Identify the applicable model instructions or contact Rheem support.
- PG&E: recognizing and responding to a gas leak (opens in a new tab)Emergency actions for suspected fuel-gas leaks.
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