Ruud Water Heaters Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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11
Ruud tankless water heater displays error code 11; burner does not ignite and water remains cold.
Ignition Failure
12
Ruud tankless water heater displays error code 12; burner lights briefly then shuts off, causing hot water to cut out.
Flame Loss During Operation
13
Ruud tankless water heater shows error code 13; unit may shut down shortly after ignition.
Combustion / Flame Rod Signal Abnormal
14
Ruud tankless water heater displays error code 14; unit shuts down and will not provide hot water.
Overheat / High Temperature Safety Shutdown
15
Ruud tankless water heater shows error code 15; unit may run at limited capacity or shut down.
Booster Fan / Secondary Fan Fault (on some models)
16
Ruud tankless water heater displays error code 16; water may be excessively hot before shutdown.
Outlet Water Temperature Too High
29
Ruud tankless water heater shows error code 29; unit may not operate in condensing mode or may shut down.
Condensate Drain / Neutralizer Fault (condensing models)
31
Ruud tankless water heater displays error code 31; unit may not start or may shut down.
Inlet Thermistor Fault
32
Ruud tankless water heater shows error code 32; unit may operate erratically or shut down.
Outlet Thermistor Fault
33
Ruud tankless water heater displays error code 33; unit may not modulate correctly.
Heat Exchanger Thermistor Fault
34
Ruud tankless water heater shows error code 34; unit may shut down or run at reduced capacity.
Combustion Air Temperature Sensor Fault
61
Ruud tankless water heater displays error code 61; fan may not start or may run erratically.
Combustion Fan Motor Fault
65
Ruud tankless water heater shows error code 65; unit may not respond correctly to recirculation or remote commands.
Communication / Remote Control Fault
72
Ruud tankless water heater displays error code 72; unit may not detect flame correctly.
Flame Sensing Circuit Error
76
Ruud tankless water heater shows error code 76; unit may not communicate with optional accessories.
Communication Error with Optional Components
79
Ruud tankless water heater displays error code 79; unit may shut down unexpectedly.
Fan Motor Current Abnormal / Overcurrent
E0
Tankless water heater powers on but does not fire; display shows E0 and unit will not enter normal operation.
Control Board Configuration / Parameter Error
E1
Tankless water heater attempts to start but shuts down with E1; no hot water is produced.
Ignition Failure / Ignition Lockout
E2
Tankless unit displays E2 and shuts down shortly after starting; water may get briefly warm then go cold.
Overheat Protection / Heat Exchanger Over-Temperature
E3
Tankless water heater shows E3 and shuts down; unit may start but quickly stops with no hot water.
Exhaust / Flue Temperature High
E4
Tankless water heater displays E4; unit may not start or may shut down during operation.
Inlet / Outlet Thermistor Fault
E5
Tankless water heater shows E5 and shuts down; water temperature may fluctuate before shutdown.
Water Flow Sensor / Flow Switch Error
E6
Tankless water heater displays E6; unit may not modulate correctly and water temperature may be unstable.
Fan Motor / Combustion Air Blower Fault
E7
Tankless water heater shows E7; unit may not ignite or may shut down intermittently.
Gas Valve / Gas Solenoid Fault
E8
Tankless water heater displays E8; unit may run at reduced output or shut down.
Fan Speed / Combustion Feedback Error
E9
Tankless water heater shows E9 and will not operate.
EEPROM / Control Board Memory Error
FVS
Ruud FVIR (flammable vapor ignition resistant) gas water heater status light flashes indicating flammable vapor sensor (FVS) lockout; burner will not light.
Flammable Vapor Sensor Lockout
LED_FLASH_1
Ruud gas water heater status light flashes 1 time every 3 seconds; pilot will not stay lit.
Thermopile / Pilot Sensor Fault
LED_FLASH_2
Ruud gas water heater status light flashes 2 times every 3 seconds; burner does not light.
Pressure Switch / Vent Safety Fault (power vent models)
LED_FLASH_3
Ruud gas water heater status light flashes 3 times every 3 seconds; burner will not light.
Flammable Vapor Sensor / Lockout Indication (alternate pattern)
Symptom
No hot water from Ruud gas tank water heater; pilot will not light or stay lit, no electronic error code present.
Pilot Ignition / Standing Pilot Failure
Symptom
Ruud electric water heater has no hot water at all; power light off, no heating.
No Power / High Limit Tripped
Symptom
Ruud electric water heater has power but water is only warm, not hot enough.
Lower Element or Thermostat Failure (Electric Tank)
Symptom
Ruud electric water heater produces only a small amount of hot water, then quickly turns lukewarm.
Upper Element or Thermostat Failure (Electric Tank)
Symptom
Ruud gas or electric water heater leaks water from the base or around fittings.
Tank or Fitting Leak
Symptom
Ruud power vent water heater blower runs but burner does not ignite; no specific error code visible to user.
Ignition Sequence Failure (Power Vent Gas Tank)
Symptom
Ruud tankless water heater does not start when a small hot water tap is opened; no error code displayed.
Minimum Flow Not Detected
Symptom
Ruud tankless water heater provides hot water that turns cold intermittently or temperature fluctuates.
Temperature Fluctuation / Cold Water Sandwich
Symptom
Ruud water heater emits a rotten egg or sulfur smell from hot water taps.
Hydrogen Sulfide Odor / Anode Reaction
Symptom
Ruud water heater makes popping, rumbling, or banging noises during heating.
Sediment Buildup / Boiling Under Sediment
Symptom
Ruud water heater shows signs of rust-colored water from hot taps.
Internal Corrosion / Anode Depletion
Symptom
Ruud water heater T&P (temperature and pressure) relief valve drips or discharges water intermittently.
Excessive Temperature or Pressure / T&P Valve Operation
Symptom
Ruud water heater vibrates excessively or makes loud humming when heating.
Vibration / Resonance
Symptom
Water from Ruud water heater is too hot; risk of scalding at fixtures.
Overheating / Thermostat Malfunction
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| 11 |
Ruud tankless water heater displays error code 11; burner does not ignite and water remains cold.
|
Ignition Failure | View Details |
| 12 |
Ruud tankless water heater displays error code 12; burner lights briefly then shuts off, causing hot water to cut out.
|
Flame Loss During Operation | View Details |
| 13 |
Ruud tankless water heater shows error code 13; unit may shut down shortly after ignition.
|
Combustion / Flame Rod Signal Abnormal | View Details |
| 14 |
Ruud tankless water heater displays error code 14; unit shuts down and will not provide hot water.
|
Overheat / High Temperature Safety Shutdown | View Details |
| 15 |
Ruud tankless water heater shows error code 15; unit may run at limited capacity or shut down.
|
Booster Fan / Secondary Fan Fault (on some models) | View Details |
| 16 |
Ruud tankless water heater displays error code 16; water may be excessively hot before shutdown.
|
Outlet Water Temperature Too High | View Details |
| 29 |
Ruud tankless water heater shows error code 29; unit may not operate in condensing mode or may shut down.
|
Condensate Drain / Neutralizer Fault (condensing models) | View Details |
| 31 |
Ruud tankless water heater displays error code 31; unit may not start or may shut down.
|
Inlet Thermistor Fault | View Details |
| 32 |
Ruud tankless water heater shows error code 32; unit may operate erratically or shut down.
|
Outlet Thermistor Fault | View Details |
| 33 |
Ruud tankless water heater displays error code 33; unit may not modulate correctly.
|
Heat Exchanger Thermistor Fault | View Details |
| 34 |
Ruud tankless water heater shows error code 34; unit may shut down or run at reduced capacity.
|
Combustion Air Temperature Sensor Fault | View Details |
| 61 |
Ruud tankless water heater displays error code 61; fan may not start or may run erratically.
|
Combustion Fan Motor Fault | View Details |
| 65 |
Ruud tankless water heater shows error code 65; unit may not respond correctly to recirculation or remote commands.
|
Communication / Remote Control Fault | View Details |
| 72 |
Ruud tankless water heater displays error code 72; unit may not detect flame correctly.
|
Flame Sensing Circuit Error | View Details |
| 76 |
Ruud tankless water heater shows error code 76; unit may not communicate with optional accessories.
|
Communication Error with Optional Components | View Details |
| 79 |
Ruud tankless water heater displays error code 79; unit may shut down unexpectedly.
|
Fan Motor Current Abnormal / Overcurrent | View Details |
| E0 |
Tankless water heater powers on but does not fire; display shows E0 and unit will not enter normal operation.
|
Control Board Configuration / Parameter Error | View Details |
| E1 |
Tankless water heater attempts to start but shuts down with E1; no hot water is produced.
|
Ignition Failure / Ignition Lockout | View Details |
| E2 |
Tankless unit displays E2 and shuts down shortly after starting; water may get briefly warm then go cold.
|
Overheat Protection / Heat Exchanger Over-Temperature | View Details |
| E3 |
Tankless water heater shows E3 and shuts down; unit may start but quickly stops with no hot water.
|
Exhaust / Flue Temperature High | View Details |
| E4 |
Tankless water heater displays E4; unit may not start or may shut down during operation.
|
Inlet / Outlet Thermistor Fault | View Details |
| E5 |
Tankless water heater shows E5 and shuts down; water temperature may fluctuate before shutdown.
|
Water Flow Sensor / Flow Switch Error | View Details |
| E6 |
Tankless water heater displays E6; unit may not modulate correctly and water temperature may be unstable.
|
Fan Motor / Combustion Air Blower Fault | View Details |
| E7 |
Tankless water heater shows E7; unit may not ignite or may shut down intermittently.
|
Gas Valve / Gas Solenoid Fault | View Details |
| E8 |
Tankless water heater displays E8; unit may run at reduced output or shut down.
|
Fan Speed / Combustion Feedback Error | View Details |
| E9 |
Tankless water heater shows E9 and will not operate.
|
EEPROM / Control Board Memory Error | View Details |
| FVS |
Ruud FVIR (flammable vapor ignition resistant) gas water heater status light flashes indicating flammable vapor sensor (FVS) lockout; burner will not light.
|
Flammable Vapor Sensor Lockout | View Details |
| LED_FLASH_1 |
Ruud gas water heater status light flashes 1 time every 3 seconds; pilot will not stay lit.
|
Thermopile / Pilot Sensor Fault | View Details |
| LED_FLASH_2 |
Ruud gas water heater status light flashes 2 times every 3 seconds; burner does not light.
|
Pressure Switch / Vent Safety Fault (power vent models) | View Details |
| LED_FLASH_3 |
Ruud gas water heater status light flashes 3 times every 3 seconds; burner will not light.
|
Flammable Vapor Sensor / Lockout Indication (alternate pattern) | View Details |
| – |
No hot water from Ruud gas tank water heater; pilot will not light or stay lit, no electronic error code present.
|
Pilot Ignition / Standing Pilot Failure | View Details |
| – |
Ruud electric water heater has no hot water at all; power light off, no heating.
|
No Power / High Limit Tripped | View Details |
| – |
Ruud electric water heater has power but water is only warm, not hot enough.
|
Lower Element or Thermostat Failure (Electric Tank) | View Details |
| – |
Ruud electric water heater produces only a small amount of hot water, then quickly turns lukewarm.
|
Upper Element or Thermostat Failure (Electric Tank) | View Details |
| – |
Ruud gas or electric water heater leaks water from the base or around fittings.
|
Tank or Fitting Leak | View Details |
| – |
Ruud power vent water heater blower runs but burner does not ignite; no specific error code visible to user.
|
Ignition Sequence Failure (Power Vent Gas Tank) | View Details |
| – |
Ruud tankless water heater does not start when a small hot water tap is opened; no error code displayed.
|
Minimum Flow Not Detected | View Details |
| – |
Ruud tankless water heater provides hot water that turns cold intermittently or temperature fluctuates.
|
Temperature Fluctuation / Cold Water Sandwich | View Details |
| – |
Ruud water heater emits a rotten egg or sulfur smell from hot water taps.
|
Hydrogen Sulfide Odor / Anode Reaction | View Details |
| – |
Ruud water heater makes popping, rumbling, or banging noises during heating.
|
Sediment Buildup / Boiling Under Sediment | View Details |
| – |
Ruud water heater shows signs of rust-colored water from hot taps.
|
Internal Corrosion / Anode Depletion | View Details |
| – |
Ruud water heater T&P (temperature and pressure) relief valve drips or discharges water intermittently.
|
Excessive Temperature or Pressure / T&P Valve Operation | View Details |
| – |
Ruud water heater vibrates excessively or makes loud humming when heating.
|
Vibration / Resonance | View Details |
| – |
Water from Ruud water heater is too hot; risk of scalding at fixtures.
|
Overheating / Thermostat Malfunction | View Details |
No matching codes found
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