Ruud Air Conditioners Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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E0
The Ruud air conditioner outdoor unit will not start; the thermostat calls for cooling, but the condenser fan and compressor are both off, and the display or board LED shows E0.
Communication Fault Between Indoor and Outdoor Control Boards
E1
The Ruud air conditioner outdoor unit starts then quickly shuts down; the diagnostic LED or display shows E1.
High-Pressure Switch Open / High Head Pressure Trip
E2
The Ruud air conditioner runs briefly then shuts off; the diagnostic display or LED indicates E2.
Low-Pressure Switch Open / Low Suction Pressure Trip
E3
The Ruud air conditioner outdoor unit runs, but the compressor does not start; the control board or diagnostic LED shows E3.
Compressor Overload / Locked Rotor or Start Failure
E4
The Ruud air conditioner stops cooling and displays E4 or flashes a fault code; the unit may run briefly then shut down.
Evaporator Coil Freeze Protection / Low Coil Temperature
E5
The Ruud air conditioner shows E5 and may shut down or run with poor cooling performance.
Outdoor Ambient Temperature Sensor Fault
E6
Ruud air conditioner displays E6; the unit may not respond properly to thermostat commands or may short-cycle.
Indoor Coil Temperature Sensor Fault
E7
Ruud air conditioner shows E7; the system may not start or may run erratically with the fan and compressor cycling unexpectedly.
Phase Loss / Phase Reversal (Three-Phase Units)
E8
Ruud air conditioner displays E8 and may shut down or limit operation during very hot weather.
Compressor Discharge Temperature High
E9
Ruud air conditioner shows E9; the unit may not start or may shut down unexpectedly.
EEPROM / Control Board Memory Error
F1
Ruud air conditioner indoor unit displays F1; the blower may not run or may run at an incorrect speed.
Indoor Blower Motor Fault (ECM/Variable Speed)
F2
Ruud air conditioner indoor unit shows F2; the system may shut down on safety and not cool.
Condensate Overflow / Float Switch Open
F3
Ruud air conditioner indoor unit displays F3; the blower may run but cooling is disabled.
Supply Air Temperature Sensor Fault
F4
Ruud air conditioner indoor unit shows F4; the system may shut down or run with poor dehumidification.
Return Air Temperature Sensor Fault
F5
Ruud air conditioner indoor unit displays F5; the blower may not start or may shut off unexpectedly.
Blower Overcurrent / Motor Protection Trip
H0
Ruud air conditioner outdoor unit shows H0; the unit may not start or may run in a limited mode.
Defrost Control / Heat Pump Mode Error (for Ruud Heat Pump AC Units)
H1
Ruud air conditioner (heat pump) displays H1; the unit may stay in defrost too long or not defrost properly.
Defrost Sensor Fault / Coil Temperature Sensor Error
H2
Ruud air conditioner (heat pump) shows H2; the unit may not switch correctly between heating and cooling modes.
Reversing Valve Fault
L1
Ruud air conditioner control board indicates L1; the unit may not start or may trip the breaker.
Line Voltage Low / Brownout Protection
L2
Ruud air conditioner control board shows L2; the unit may lock out after repeated faults.
Lockout Due to Repeated Safety Trips
Symptom
Ruud air conditioner causes lights to dim or breaker to trip when starting.
High Inrush Current / Electrical Overload
Symptom
Ruud air conditioner emits a burning or electrical smell when starting or running.
Overheating Electrical Component or Motor
Symptom
Ruud air conditioner indoor unit frequently trips the condensate safety switch, shutting down cooling.
Chronic Condensate Management Problem
Symptom
Ruud air conditioner indoor unit vibrates excessively and produces rumbling noise when blower runs.
Blower Wheel Imbalance or Mounting Issue
Symptom
Ruud air conditioner outdoor coil repeatedly ices over in cooling mode, even after thawing.
Chronic Evaporator/Outdoor Coil Freezing (for certain configurations)
Symptom
Ruud air conditioner outdoor unit runs in cold weather when it should be off (for straight cool systems).
Stuck Contactor or Thermostat Control Fault
Symptom
Ruud air conditioner produces a musty or moldy smell when the blower starts.
Biological Growth on Evaporator Coil or in Drain Pan
Symptom
Ruud air conditioner runs continuously and struggles to reach set temperature, even in moderate weather.
Insufficient Cooling Capacity / Efficiency Loss
Symptom
Ruud air conditioner thermostat display is blank and system does not respond.
Loss of 24V Control Power
Symptom
Ruud outdoor unit is excessively noisy, with rattling, banging, or metal-on-metal sounds during operation.
Mechanical Noise / Fan or Panel Vibration
Symptom
The Ruud air conditioner indoor blower runs but the air is not cold; the outdoor unit fan runs but the suction line is not very cold, and the home does not cool.
Low Refrigerant Charge / Refrigerant Leak
Symptom
The Ruud air conditioner runs but makes a loud buzzing or humming noise at the outdoor unit; the fan may not start or is slow to start.
Failed Outdoor Fan/Compressor Capacitor
Symptom
The Ruud air conditioner short cycles; the outdoor unit turns on and off every few minutes without reaching the set temperature.
Short Cycling / Improper Control or Capacity
Symptom
The Ruud outdoor unit fan runs but the compressor does not; the unit hums briefly then clicks off, resulting in no cooling.
Compressor Start Failure / Locked Rotor
Symptom
The Ruud outdoor unit runs but the indoor blower does not; there is weak or no airflow from the supply registers.
Indoor Blower Motor Failure
Symptom
The outdoor Ruud air conditioner unit will not start at all; the indoor blower runs but the condenser fan and compressor are silent, with no obvious error code visible.
No Power to Outdoor Unit
Symptom
Water leaking from Ruud indoor air handler or furnace cabinet, dripping onto floor or ceiling below.
Condensate Drain Clog / Pan Overflow
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E0 |
The Ruud air conditioner outdoor unit will not start; the thermostat calls for cooling, but the condenser fan and compressor are both off, and the display or board LED shows E0.
|
Communication Fault Between Indoor and Outdoor Control Boards | View Details |
| E1 |
The Ruud air conditioner outdoor unit starts then quickly shuts down; the diagnostic LED or display shows E1.
|
High-Pressure Switch Open / High Head Pressure Trip | View Details |
| E2 |
The Ruud air conditioner runs briefly then shuts off; the diagnostic display or LED indicates E2.
|
Low-Pressure Switch Open / Low Suction Pressure Trip | View Details |
| E3 |
The Ruud air conditioner outdoor unit runs, but the compressor does not start; the control board or diagnostic LED shows E3.
|
Compressor Overload / Locked Rotor or Start Failure | View Details |
| E4 |
The Ruud air conditioner stops cooling and displays E4 or flashes a fault code; the unit may run briefly then shut down.
|
Evaporator Coil Freeze Protection / Low Coil Temperature | View Details |
| E5 |
The Ruud air conditioner shows E5 and may shut down or run with poor cooling performance.
|
Outdoor Ambient Temperature Sensor Fault | View Details |
| E6 |
Ruud air conditioner displays E6; the unit may not respond properly to thermostat commands or may short-cycle.
|
Indoor Coil Temperature Sensor Fault | View Details |
| E7 |
Ruud air conditioner shows E7; the system may not start or may run erratically with the fan and compressor cycling unexpectedly.
|
Phase Loss / Phase Reversal (Three-Phase Units) | View Details |
| E8 |
Ruud air conditioner displays E8 and may shut down or limit operation during very hot weather.
|
Compressor Discharge Temperature High | View Details |
| E9 |
Ruud air conditioner shows E9; the unit may not start or may shut down unexpectedly.
|
EEPROM / Control Board Memory Error | View Details |
| F1 |
Ruud air conditioner indoor unit displays F1; the blower may not run or may run at an incorrect speed.
|
Indoor Blower Motor Fault (ECM/Variable Speed) | View Details |
| F2 |
Ruud air conditioner indoor unit shows F2; the system may shut down on safety and not cool.
|
Condensate Overflow / Float Switch Open | View Details |
| F3 |
Ruud air conditioner indoor unit displays F3; the blower may run but cooling is disabled.
|
Supply Air Temperature Sensor Fault | View Details |
| F4 |
Ruud air conditioner indoor unit shows F4; the system may shut down or run with poor dehumidification.
|
Return Air Temperature Sensor Fault | View Details |
| F5 |
Ruud air conditioner indoor unit displays F5; the blower may not start or may shut off unexpectedly.
|
Blower Overcurrent / Motor Protection Trip | View Details |
| H0 |
Ruud air conditioner outdoor unit shows H0; the unit may not start or may run in a limited mode.
|
Defrost Control / Heat Pump Mode Error (for Ruud Heat Pump AC Units) | View Details |
| H1 |
Ruud air conditioner (heat pump) displays H1; the unit may stay in defrost too long or not defrost properly.
|
Defrost Sensor Fault / Coil Temperature Sensor Error | View Details |
| H2 |
Ruud air conditioner (heat pump) shows H2; the unit may not switch correctly between heating and cooling modes.
|
Reversing Valve Fault | View Details |
| L1 |
Ruud air conditioner control board indicates L1; the unit may not start or may trip the breaker.
|
Line Voltage Low / Brownout Protection | View Details |
| L2 |
Ruud air conditioner control board shows L2; the unit may lock out after repeated faults.
|
Lockout Due to Repeated Safety Trips | View Details |
| – |
Ruud air conditioner causes lights to dim or breaker to trip when starting.
|
High Inrush Current / Electrical Overload | View Details |
| – |
Ruud air conditioner emits a burning or electrical smell when starting or running.
|
Overheating Electrical Component or Motor | View Details |
| – |
Ruud air conditioner indoor unit frequently trips the condensate safety switch, shutting down cooling.
|
Chronic Condensate Management Problem | View Details |
| – |
Ruud air conditioner indoor unit vibrates excessively and produces rumbling noise when blower runs.
|
Blower Wheel Imbalance or Mounting Issue | View Details |
| – |
Ruud air conditioner outdoor coil repeatedly ices over in cooling mode, even after thawing.
|
Chronic Evaporator/Outdoor Coil Freezing (for certain configurations) | View Details |
| – |
Ruud air conditioner outdoor unit runs in cold weather when it should be off (for straight cool systems).
|
Stuck Contactor or Thermostat Control Fault | View Details |
| – |
Ruud air conditioner produces a musty or moldy smell when the blower starts.
|
Biological Growth on Evaporator Coil or in Drain Pan | View Details |
| – |
Ruud air conditioner runs continuously and struggles to reach set temperature, even in moderate weather.
|
Insufficient Cooling Capacity / Efficiency Loss | View Details |
| – |
Ruud air conditioner thermostat display is blank and system does not respond.
|
Loss of 24V Control Power | View Details |
| – |
Ruud outdoor unit is excessively noisy, with rattling, banging, or metal-on-metal sounds during operation.
|
Mechanical Noise / Fan or Panel Vibration | View Details |
| – |
The Ruud air conditioner indoor blower runs but the air is not cold; the outdoor unit fan runs but the suction line is not very cold, and the home does not cool.
|
Low Refrigerant Charge / Refrigerant Leak | View Details |
| – |
The Ruud air conditioner runs but makes a loud buzzing or humming noise at the outdoor unit; the fan may not start or is slow to start.
|
Failed Outdoor Fan/Compressor Capacitor | View Details |
| – |
The Ruud air conditioner short cycles; the outdoor unit turns on and off every few minutes without reaching the set temperature.
|
Short Cycling / Improper Control or Capacity | View Details |
| – |
The Ruud outdoor unit fan runs but the compressor does not; the unit hums briefly then clicks off, resulting in no cooling.
|
Compressor Start Failure / Locked Rotor | View Details |
| – |
The Ruud outdoor unit runs but the indoor blower does not; there is weak or no airflow from the supply registers.
|
Indoor Blower Motor Failure | View Details |
| – |
The outdoor Ruud air conditioner unit will not start at all; the indoor blower runs but the condenser fan and compressor are silent, with no obvious error code visible.
|
No Power to Outdoor Unit | View Details |
| – |
Water leaking from Ruud indoor air handler or furnace cabinet, dripping onto floor or ceiling below.
|
Condensate Drain Clog / Pan Overflow | View Details |
No matching codes found
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