Keystone
Keystone Humidifiers & Dehumidifiers Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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E1
Dehumidifier stops running and displays E1 on the control panel; buttons may not respond or unit may not start.
Room Temperature Sensor Failure
E2
Dehumidifier displays E2 and stops dehumidifying; fan may still run or unit may shut down completely.
Evaporator Coil Temperature Sensor Failure
E3
Dehumidifier shows E3 and will not run the compressor; fan may operate intermittently.
Humidity Sensor (RH Sensor) Failure
E4
Dehumidifier displays E4 and shuts down; compressor will not start.
Refrigerant System / Defrost Protection Error (Low Coil Temperature or Sensor Logic Fault)
E5
Dehumidifier shows E5 and stops; may attempt to start and then shut off quickly.
Compressor Overload / High Temperature Protection Error
E6
Dehumidifier displays E6 and will not operate normally; may beep repeatedly.
Communication Error Between Display Board and Main Control Board
E7
Dehumidifier shows E7 and will not start or shuts down shortly after starting.
Internal EEPROM / Memory Error on Control Board
EC
Dehumidifier displays EC and stops cooling; fan may still run.
Refrigerant System / Sensor Error (Low Refrigerant or Coil Sensor Fault)
F0
Humidifier or dehumidifier displays F0 and stops operating or runs erratically.
General Sensor Fault / Sensor Out of Range
F1
Humidifier displays F1 and will not respond to humidity settings correctly.
Humidity Sensor Circuit Error
F2
Humidifier or dehumidifier shows F2 and stops or runs only briefly.
Temperature Sensor Error (Ambient or Coil)
F3
Humidifier displays F3 and will not produce mist or will shut down.
Water Level Sensor / Float Error
F4
Humidifier shows F4 and stops generating mist; fan may still run.
Ultrasonic Transducer / Nebulizer Error (Humidifier Only)
HI
Dehumidifier display shows HI for temperature or humidity and may not control properly.
High Ambient Temperature or Humidity Indication / Sensor Out of Range
LO
Dehumidifier display shows LO and unit may not start or may run only the fan.
Low Ambient Temperature Protection
P1
Dehumidifier displays P1 and stops dehumidifying; fan may continue to run.
Defrost Mode Active (Automatic Coil Defrost)
P2
Dehumidifier displays P2 and stops running; bucket is full or nearly full.
Bucket Full / Water Tank Full Protection
Symptom
Buttons on the dehumidifier control panel do not respond or respond intermittently.
Keypad / Control Panel Failure
Symptom
Dehumidifier blows warm air but room humidity does not decrease significantly.
Inefficient Dehumidification / Partial Refrigerant Loss
Symptom
Dehumidifier bucket full light stays on even when the bucket is empty and properly installed.
False Bucket Full Indication
Symptom
Dehumidifier bucket overflows or leaks water onto the floor.
Water Leakage / Drainage Failure
Symptom
Dehumidifier display and buttons work, but fan does not run at all.
Fan Motor Not Running
Symptom
Dehumidifier display is blank or segments are missing, but the unit may still run.
Display Panel Failure
Symptom
Dehumidifier does not power on at all; no lights or display, no fan noise.
No Power / Dead Unit
Symptom
Dehumidifier emits a musty or moldy odor from the air outlet.
Biological Growth / Odor in Air Path
Symptom
Dehumidifier fan runs but no air seems to come out of the front grille.
Airflow Obstruction / Blower Failure
Symptom
Dehumidifier freezes up; evaporator coil becomes a solid block of ice.
Coil Icing / Frost Buildup
Symptom
Dehumidifier is very noisy during operation; rattling, buzzing, or grinding sounds are heard.
Excessive Noise / Vibration
Symptom
Dehumidifier powers on but compressor never starts; fan runs continuously and humidity is not reduced.
Compressor Not Starting
Symptom
Dehumidifier runs briefly then shuts off; bucket is not full and no error code is shown.
Short Cycling / Overheat or Protection Trip
Symptom
Dehumidifier runs but does not collect water; bucket remains dry even after hours of operation.
No Dehumidification / Poor Moisture Removal
Symptom
Dehumidifier shuts off and will not restart for several minutes even though the bucket is not full.
Compressor Short-Cycle Protection / Time Delay
Symptom
Dehumidifier vibrates excessively and may move or "walk" on the floor during operation.
Severe Vibration
Symptom
Humidifier leaks water from the base or around the tank area.
Water Leakage (Humidifier)
Symptom
Humidifier or dehumidifier has a burning or electrical smell during operation.
Overheating Electrical Component
Symptom
Humidifier runs but produces little or no mist.
Low Mist Output (Humidifier)
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E1 |
Dehumidifier stops running and displays E1 on the control panel; buttons may not respond or unit may not start.
|
Room Temperature Sensor Failure | View Details |
| E2 |
Dehumidifier displays E2 and stops dehumidifying; fan may still run or unit may shut down completely.
|
Evaporator Coil Temperature Sensor Failure | View Details |
| E3 |
Dehumidifier shows E3 and will not run the compressor; fan may operate intermittently.
|
Humidity Sensor (RH Sensor) Failure | View Details |
| E4 |
Dehumidifier displays E4 and shuts down; compressor will not start.
|
Refrigerant System / Defrost Protection Error (Low Coil Temperature or Sensor Logic Fault) | View Details |
| E5 |
Dehumidifier shows E5 and stops; may attempt to start and then shut off quickly.
|
Compressor Overload / High Temperature Protection Error | View Details |
| E6 |
Dehumidifier displays E6 and will not operate normally; may beep repeatedly.
|
Communication Error Between Display Board and Main Control Board | View Details |
| E7 |
Dehumidifier shows E7 and will not start or shuts down shortly after starting.
|
Internal EEPROM / Memory Error on Control Board | View Details |
| EC |
Dehumidifier displays EC and stops cooling; fan may still run.
|
Refrigerant System / Sensor Error (Low Refrigerant or Coil Sensor Fault) | View Details |
| F0 |
Humidifier or dehumidifier displays F0 and stops operating or runs erratically.
|
General Sensor Fault / Sensor Out of Range | View Details |
| F1 |
Humidifier displays F1 and will not respond to humidity settings correctly.
|
Humidity Sensor Circuit Error | View Details |
| F2 |
Humidifier or dehumidifier shows F2 and stops or runs only briefly.
|
Temperature Sensor Error (Ambient or Coil) | View Details |
| F3 |
Humidifier displays F3 and will not produce mist or will shut down.
|
Water Level Sensor / Float Error | View Details |
| F4 |
Humidifier shows F4 and stops generating mist; fan may still run.
|
Ultrasonic Transducer / Nebulizer Error (Humidifier Only) | View Details |
| HI |
Dehumidifier display shows HI for temperature or humidity and may not control properly.
|
High Ambient Temperature or Humidity Indication / Sensor Out of Range | View Details |
| LO |
Dehumidifier display shows LO and unit may not start or may run only the fan.
|
Low Ambient Temperature Protection | View Details |
| P1 |
Dehumidifier displays P1 and stops dehumidifying; fan may continue to run.
|
Defrost Mode Active (Automatic Coil Defrost) | View Details |
| P2 |
Dehumidifier displays P2 and stops running; bucket is full or nearly full.
|
Bucket Full / Water Tank Full Protection | View Details |
| – |
Buttons on the dehumidifier control panel do not respond or respond intermittently.
|
Keypad / Control Panel Failure | View Details |
| – |
Dehumidifier blows warm air but room humidity does not decrease significantly.
|
Inefficient Dehumidification / Partial Refrigerant Loss | View Details |
| – |
Dehumidifier bucket full light stays on even when the bucket is empty and properly installed.
|
False Bucket Full Indication | View Details |
| – |
Dehumidifier bucket overflows or leaks water onto the floor.
|
Water Leakage / Drainage Failure | View Details |
| – |
Dehumidifier display and buttons work, but fan does not run at all.
|
Fan Motor Not Running | View Details |
| – |
Dehumidifier display is blank or segments are missing, but the unit may still run.
|
Display Panel Failure | View Details |
| – |
Dehumidifier does not power on at all; no lights or display, no fan noise.
|
No Power / Dead Unit | View Details |
| – |
Dehumidifier emits a musty or moldy odor from the air outlet.
|
Biological Growth / Odor in Air Path | View Details |
| – |
Dehumidifier fan runs but no air seems to come out of the front grille.
|
Airflow Obstruction / Blower Failure | View Details |
| – |
Dehumidifier freezes up; evaporator coil becomes a solid block of ice.
|
Coil Icing / Frost Buildup | View Details |
| – |
Dehumidifier is very noisy during operation; rattling, buzzing, or grinding sounds are heard.
|
Excessive Noise / Vibration | View Details |
| – |
Dehumidifier powers on but compressor never starts; fan runs continuously and humidity is not reduced.
|
Compressor Not Starting | View Details |
| – |
Dehumidifier runs briefly then shuts off; bucket is not full and no error code is shown.
|
Short Cycling / Overheat or Protection Trip | View Details |
| – |
Dehumidifier runs but does not collect water; bucket remains dry even after hours of operation.
|
No Dehumidification / Poor Moisture Removal | View Details |
| – |
Dehumidifier shuts off and will not restart for several minutes even though the bucket is not full.
|
Compressor Short-Cycle Protection / Time Delay | View Details |
| – |
Dehumidifier vibrates excessively and may move or "walk" on the floor during operation.
|
Severe Vibration | View Details |
| – |
Humidifier leaks water from the base or around the tank area.
|
Water Leakage (Humidifier) | View Details |
| – |
Humidifier or dehumidifier has a burning or electrical smell during operation.
|
Overheating Electrical Component | View Details |
| – |
Humidifier runs but produces little or no mist.
|
Low Mist Output (Humidifier) | View Details |
No matching codes found
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