The status light
Rheem water heater codes,
and what each means
A Rheem gas tank’s control blinks its status light in a pattern. Count the flashes, note the color if it has one, and write it down before you touch the knob.
Rheem gas tank status light (Performance and Professional atmospheric tanks)
The light on the gas control knob. One blue blink every three seconds is normal.
Rheem gas water heater status light codes| Blinks | What it means | What to do |
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| Light off or solid | The control is off or the pilot is out; solid means it just went out and is cooling down | Relight by the label on the tank. If it won’t stay lit, call |
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| 2 red | Pilot is lit but the thermopile voltage is low | A thermopile or pilot repair |
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| 4 red | High temperature shutdown: the water got too hot | Leave it off and call |
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| 5 red | Temperature sensor failure | A sensor repair |
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| 7 red | Gas control or valve failure | Usually a new gas control |
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| 8 red | False pilot flame signal | Call: the control sees a flame that isn’t there |
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Source: Rheem, Combination Gas Control Status Light Troubleshooting. Codes vary by model and control board: the chart printed on your unit, or its manual, is the final word.
Rheem power vent tanks (the ones with a fan on top)
Rheem power vent water heater codes| Flashes | What it means | What to do |
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| 2 | Pressure switch failed closed | Call |
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| 3 | Pressure switch or blower thermal switch open | Check the vent outside for a blockage, then call |
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| 4 | The high-limit (TCO) tripped | Make sure the tank is full of water; then call |
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| 6 then 1 | Locked out: it tried and failed to light | Check the gas is on; then call |
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| 6 then 3 | Locked out: the flame went out | Call |
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| 7 | Locked out: the flammable vapor sensor tripped | Air out the room, look for stored gas cans or paint, and call. Don’t tamper with the sensor |
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Source: Rheem, Gas Valve LED Codes, power vent. Codes vary by model and control board: the chart printed on your unit, or its manual, is the final word.
Rheem tankless (RTGH, RTG, Performance Plus and Platinum)
IKONIC models print the same faults with A0 in front: A011, A012, A029.
Rheem tankless water heater error codes| Code | What it means | What to do |
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| 11 | No ignition: the flame never lit | Check the gas valve to the heater is fully open |
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| 12 | Flame lit, then went out | Gas service interrupted, or a propane tank running low |
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| 1L | Lime building up in the heat exchanger | A descale flush, before it does permanent damage |
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| 29 | Condensate isn’t draining (a clogged neutralizer) | A drain and neutralizer service |
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| 90 or 99 | Air intake or vent blocked | Clear snow, leaves or nests from the vents outside |
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| 14 | Overheat limiter active | Usually the gas supply or venting; call |
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| P1 | Not enough water flow to fire (under 0.4 gallons a minute) | Clean the inlet filter or aerator; then call |
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| 88 | Maintenance reminder | It’s due for a flush; left alone it will shut down |
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Source: Rheem tankless troubleshooting guide. Codes vary by model and control board: the chart printed on your unit, or its manual, is the final word.
Rheem and Ruud two-stage furnaces (the display on the control board)
Rheem and Ruud condensing furnaces show a two-digit code on the board’s display. Check the display is the right way up before you read it.
Rheem furnace error codes| Code | What it means | What it usually takes |
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| 10 | One-hour lockout after four failed ignitions | Gas, igniter or flame sensor |
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| 11 | Failed ignition | Often a dirty or loose flame sensor, or the gas turned off |
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| 12 | Low flame sense | A flame sensor cleaning, or a poor ground |
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| 22 | Main limit open | Airflow first: the filter and the blower |
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| 26 | Line and neutral reversed | A wiring fix |
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| 33 | Rollout switch open | Call: combustion air, a blocked vent or the heat exchanger |
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| 45, 46 | Low pressure switch open with the inducer running | The vent, drain or inducer |
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| 57 | High pressure switch open | A blocked intake or exhaust |
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| 59 | Blocked drain: water backing up in the furnace | A clogged drain or trap |
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| 61 | Blower can’t run | The blower motor |
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Source: Rheem (-)96T installation instructions. Codes vary by model and control board: the chart printed on your unit, or its manual, is the final word.
Rheem ProTerra heat pump water heaters
Rheem ProTerra hybrid water heater codes| Code | What it means | What to do |
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| A108 | Condensate line blocked | Clear the condensate line |
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| A107 | Water detected on the floor | Look for the leak; call |
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| T131 | Clean the air filter | Slide the filter out and wash it |
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| A008 | Dry fire: it tried to heat without water | Call |
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| A200 | High water temperature (ECO) | Call |
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Source: Rheem ProTerra troubleshooting alarm codes. Codes vary by model and control board: the chart printed on your unit, or its manual, is the final word.