Rheem Gas Water Heater Won't Light: What to Check
On this page (6 sections)
The Short Answer: When a Rheem gas tank will not light at all, the cause is usually no gas reaching it, a control turned off, an igniter that does not spark, or a safety lockout. First identify your ignition type from the lighting label on the heater. Confirm the gas supply, follow that label once, and if there is still no flame, stop and call a technician rather than repeating attempts.
Which kind of Rheem do you have?
The lighting instructions label on the front of the heater tells you, and it is the only procedure you should follow.
- Standing pilot with a push-button igniter. The gas control knob has OFF, PILOT, and ON (or a temperature dial with a pilot position). You press and hold a button while clicking the igniter and watch the pilot through a small window. Many standard Rheem, Ruud, and Richmond tanks work this way.
- Electronic ignition. No pilot to light by hand; the label says not to light it manually. These have a gas control with a status light, and power-vent models also have a blower and a 120-volt plug. They light automatically when the control calls for heat.
If the problem is a pilot that lights but goes out when you release the button, that is a different fault; see Rheem pilot light will not stay lit.
Owner checks
- Gas supply. The shutoff valve on the gas line to the heater should be open (handle in line with the pipe). Check that other gas appliances work. On propane, check the tank level.
- Control position. Make sure the knob is not left on OFF or in a vacation setting.
- Power for electronic and power-vent models. Confirm the heater is plugged in and the outlet or breaker has power. A standing-pilot tank does not need electricity.
- The status light. On electronic models, count the flashes and compare them to the label on the gas control. Rheem’s flash patterns differ by control, so the label on your heater is the only reliable key. Specific patterns are covered in Rheem 7 blue flashes and Rheem 9 red flashes; a dark light is covered in Rheem no status light.
- One lighting attempt per the label. On a standing pilot, watch through the window for a spark when you press the igniter. If there is no spark, or a spark but no pilot after the label’s procedure, stop.
Do not loosen gas fittings to check for gas or to “bleed air,” and do not remove the sealed combustion chamber door.
Why Rheem tanks lock out
Since the mid-2000s, gas tanks sold in the U.S. have flammable-vapor-ignition-resistant (FVIR) designs. If the heater senses flammable vapors or overheating in the combustion chamber, it shuts down and may not relight until a technician checks it. Lint, dust, or debris clogging the air intake at the base can also starve the burner. Keep gasoline, paint, and solvents away from the heater, and vacuum around the base from the outside.
What a technician checks
A technician confirms gas pressure at the control, inspects the igniter electrode and wire, checks the pilot orifice for blockage, and measures the output of the thermocouple or thermopile once a pilot is established. On electronic models they read the control’s fault history, check the flame sensor and, on power-vent units, the blower and pressure switch. They also inspect the combustion air intake and look for signs of overheating.
Repair or replace
Igniters, thermocouples, thermopiles, and pilot assemblies are routine repairs. A gas control valve costs more but is still a part replacement. If the heater is near the end of its life, or there are signs of a tank leak such as water in the burner area or rust under the tank, replacement is the better investment.
Related: water heater burner not lighting and Rheem failed ignition lockout.
Frequently Asked Questions
Q: Can I light a Rheem with a match or lighter? A: Only if the lighting label on your heater describes manual lighting. Most modern Rheem tanks have sealed combustion chambers and say not to use a match. If the built-in igniter does not work, have it repaired.
Q: The heater clicks but never lights. Is the igniter bad? A: Clicking with a visible spark means the igniter is working and gas is not reaching the pilot, or a safety is holding the valve closed. Clicking with no spark points to the igniter or its wire. Either way, stop after one attempt and call a technician.
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: 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.
- CPSC: carbon monoxide fact sheet (opens in a new tab)Carbon monoxide hazards and emergency response.
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