Delta VFD-EL-W Series Drive Fault Codes List
Access the complete reference guide for Delta VFD-EL-W economic drive fault codes. Learn to diagnose PID feedback errors, overload trips, and reset this compact drive.
This guide provides the most updated reference for 2026 to help you interpret codes on this compact economic drive.
Delta VFD-EL-W Fault Codes Reference Table
| Fault Code | Cause & Solution |
| EF External fault |
Cause: 1. When multi-function input terminals (MI1–MI4) are set to external fault, the AC motor drive stops output. 2. When changing the communication address 2002H bit0 = 1, the drive stops output. ‹ Soultion: 1. The “EF” disappears once the signal source is cleared and reset. |
| bb External Base Block |
Cause: 1. When the external input terminals (B.B) (MI1–MI4) are active, the AC motor drive stops output. 2. When changing the communication address 2002H bit2 = 1, the drive stops output. Soultion: 1. The “bb” disappears once the signal source is cleared. |
| cE-- Communication Fault |
Cause: Communication Fault. Soultion: 1. Check the RJ45 connection between the AC motor drive for loose wires and wiring to the correct pins. 2. Check if the communication protocol is properly set. 3. Refer to Parameter Group 09 Communication Parameters in Chapter 4 for detailed information. |
| oc Overcurrent |
Cause: Output current of the AC drive exceeds the OC level ‹ Soultion: - Extend the accel/decel time - Check whether the motor rating and the AC drive rating match up with each other - Check whether there is short-circuit among U-V-W of the AC drive - Check whether the wiring to the motor is short-circuited or grounded - Check whether the screw between the AC drive and the motor is tightened or not - Check whether the motor is over loaded |
| ov/ou overvoltage |
Cause: DC voltage of the main
circuit exceeds the over-voltage detection level - The DC bus voltage has exceeded its maximum allowable value. Soultion: - Check whether the input voltage is within the scope of the rated input voltage of the AC drive, and monitor whether there is any occurrence of the voltage transients - If it is of the motor inertia uprising voltage that caused the exceeding voltage on the DC high-voltage side within the AC drive, the solution is to extend the accel/decel time or install the braking resistor (optional) |
| oH1 Overheating |
Cause: Overheating- Heat sink temperature too high Soultion: 1. Ensure that the ambient temperature falls within the specified temperature range. 2. Make sure that the ventilation holes are not obstructed. 3. Remove any foreign objects from the heatsinks and check for possible dirty heat sink fins. 4. Check the fan and clean it. 5. Provide enough spacing for adequate ventilation |
| Lu/Lv Low Voltage |
Cause: DC high-voltage side is exceedingly low within the AC
drive Soultion: - Check whether the input power voltage is normal - Check whether the loading will be put on another unexpected heavy loading - Whether the 3-phase model is of the single-phase power input or the phase-lacking |
| oL overload |
Cause: AC drive overload- Output current exceeds the AC
drive-bearable current; e.g. could sustain for 60 seconds if the output is
150% of the AC drive rated current. ‹ Soultion: - Decrease the loading and extend the acceleration time - Check whether the motor is overloaded - Reduce the torque compensation setting (Pr.07.02). - Increase the AC drive output capacity |
| oL1 Overload 1 |
Cause: Overload 1- Internal electronic overload trip Soultion: 1. Check for possible motor overload. 2. Check electronic thermal overload setting. 3. Use a higher power motor. 4. Reduce the current level so that the drive output current does not exceed the value set by the Motor Rated Current Pr.07-00. |
| oL2 Motor overload |
Cause: OL2- motor overload Motor with exceedingly great loading ‹ Soultion: - Check whether the loading of the motor is too great - Adjust the over-torque detection setting to an appropriate setting (Pr.06-03 to Pr.06-05). |
| HPF1 CC (current clamp) |
Meaning: cc (current clamp) hardware protection error when power is
ON. Cause & Solution: 1. Hardware failure – Cycle the power. 2. After this same fault comes then there is an hardware issue in drive need to repair or replace drive. |
| HPF2 OV hardware fault |
Cause: OV hardware error Soultion: 1. Re-power on to try it. 2. After this same fault comes then there is an hardware issue in drive need to repair or replace drive. |
| HPF4 OC hardware fault |
Cause: Occ hardware error Soultion: 1. Reboots the power. 2. After this same fault comes then there is an hardware issue in drive need to repair or replace drive. |
| bb External Base Block |
Cause: 1. When the external input terminals (B.B) (MI1–MI4) are active, the AC motor drive stops output. 2. When changing the communication address 2002H bit2 = 1, the drive stops output. Soultion: 1. The “bb” disappears once the signal source is cleared. |
| ocA Over-current during acceleration |
Cause: Over-current during acceleration (Output current exceeds
triple rated current during acceleration.). Soultion: 1. Short-circuit at motor output: Check for possible poor insulation at the output lines. 2. Acceleration Time too short: Increase the Acceleration Time. 3. AC motor drive output power is too small: Replace the AC motor drive with the next higher power model. |
| ocd Over-current during deceleration |
Cause: Over-current during deceleration (Output current exceeds
triple rated current during deceleration.) Soultion: 1. Short-circuit at motor output: Check for possible poor insulation at the output line. 2. Deceleration Time too short: Increase the Deceleration Time. 3. AC motor drive output power is too small: Replace the AC motor drive with the next higher power model. |
| ocn Over-current during steady state operation |
Cause: Over-current during steady state operation (Output current
exceeds triple rated current during constant speed.) Soultion: 1. Short-circuit at motor output: Check for possible poor insulation at the output line. 2. Sudden increase in motor loading: Check for possible motor stall. 3. AC motor drive output power is too small: Replace the AC motor drive with the next higher power model. |
| EF External fault |
Cause: 1. When multi-function input terminals (MI1–MI4) are set to external fault, the AC motor drive stops output. 2. When changing the communication address 2002H bit0 = 1, the drive stops output. ‹ Soultion: 1. The “EF” disappears once the signal source is cleared and reset. |
| cF1.0 Internal EEPROM can not be programmed |
Cause: Internal EEPROM can not be programmed. Soultion: 1. Press “RESET” key to the factory setting 2. After this same fault comes then there is an hardware issue in drive need to repair or replace drive. |
| cF1.1 Internal EEPROM can not be programmed |
Cause: Internal EEPROM can not be programmed. Soultion: 1. Press “RESET” key to the factory setting 2. After this same fault comes then there is an hardware issue in drive need to repair or replace drive. |
| cF2.0 Internal EEPROM can not be read |
Cause: Internal EEPROM can not be read. Soultion: 1. Press “RESET” key to the factory setting 2. After this same fault comes then there is an hardware issue in drive need to repair or replace drive. |
| cF2.1 Internal EEPROM can not be read |
Cause: Internal EEPROM can not be read. Soultion: 1. Press “RESET” key to the factory setting 2. After this same fault comes then there is an hardware issue in drive need to repair or replace drive. |
| cF3.0 U-phase error |
Cause: Wiring detection fault U-phase error. Soultion: There is an hardware or software issue in drive. Need to repair or replace drive. |
| cF3.1 V-phase error |
Cause: Wiring detection fault V-phase error. Soultion: There is an hardware or software issue in drive. Need to repair or replace drive. |
| cF3.2 W-phase error |
Cause: Wiring detection fault W-phase error. Soultion: There is an hardware or software issue in drive. Need to repair or replace drive. |
| cF3.3 Wiring detection fault |
Cause: DC bus wiring detection error. Soultion: There is an hardware or software issue in drive. Need to repair or replace drive. |
| cF3.4 Wiring detection fault |
Cause: Temperature sensor error. Soultion: There is an hardware or software issue in drive. Need to repair or replace drive. |
| cFA Auto accel/decel failure |
Cause: Auto accel/decel failure. Soultion: 1. Check if the motor is suitable for operation by AC motor drive. 2. Check if the regenerative energy is too large. 3. Load may have changed suddenly. |
| cE-- Communication Fault |
Cause: Communication Fault. Soultion: 1. Check the RJ45 connection between the AC motor drive for loose wires and wiring to the correct pins. 2. Check if the communication protocol is properly set. 3. Refer to Parameter Group 09 Communication Parameters in Chapter 4 for detailed information. |
| FbE PID feedback signal error |
Cause: PID feedback signal error. Soultion: 1. Check the parameter settings (Pr.10.01) and AVI/ACI wiring. 2. Check for possible fault between the system response time and the PID feedback signal detection time (Pr.10.08) |
| CodE Software protection failure |
Cause: Software protection failure.(Password locked) Soultion: There is an hardware or software issue in drive. Need to repair or replace drive. |
| AErr Analog signal error |
Cause: Analog input current loss (including all analog 4–20 mA
signals) – When the analog input is lower than 4 mA (only detects analog input 4–20 mA) Solution: 1. Loose or broken ACI wiring – Tighten the terminals again. – Replace with a new cable. 2. External device error – Replace with a new device. 3. Hardware error – If the AErr error still occurs after checking all the wiring, return to the factory for repair. |
| dEu Unusual PID feedback |
Cause: Unusual PID feedback. Soultion: 1. Check if wiring for PID feedback is correct and the parameter of PID feedback is properly set. |
| PHL Phase loss |
Cause: Power input phase-lacking Phase-lacking within the input
power of the AC drive Three imbalanced conditions existed within the input
voltage ‹ Soultion: - Check whether the power voltage is normal. - Check whether the screw at the input power terminal is tightened. |
| oPHL Output phase loss |
Cause: Output phase loss of the drive. This fault also comes when
you run drive without motor or one of phase is not connected. Solution: 1. Unbalanced three-phase impedance of the motor Replace the motor. 2. Check if the wiring is incorrect Check the cable. – Replace the cable. 3. Check if the motor is a single-phase motor – Choose a three-phase motor. 4. Check if the current sensor is broken – Check if the control board cable is loose. If yes, reconnect the cable and run the drive to test. If the error still occurs, return to the factory for repair. – Check if the three-phase current is balanced with a current clamp meter. If the current is balanced and the oPHL error still shows on the display, then need to repair or replace drive. 5. Check if capacity of the drive is larger than the motor – Choose a drive’s capacity matches a motor’s. |
How to Read VFD-EL-W Faults (Keypad Diagnostics)
The VFD-EL-W is designed for “install and forget” applications. In 2026, troubleshooting rarely involves PC software due to the economic nature of the drive. Instead, use these onboard tools:
- 7-Segment LED Display: The display indicates the drive status.
- Flashing Code: If the drive stops and flashes a code (like “oc”), this is a hard fault.
- PID Feedback Monitoring: Since the EL-W is often used for simple water pressure control, you can set the display (via the Mode button) to show the feedback signal (b). If the drive runs to maximum speed and trips on pressure error, checking this “b” value tells you if your sensor is broken.
- Parameter Reset: If the drive acts erratically or parameters have been tampered with, the EL-W can be quickly restored. Set Parameter 00.02 to 9 (for 50Hz defaults) or 10 (for 60Hz defaults).
- Terminal Status: Use a multimeter to verify the AVI (Analog Voltage Input). On economic drives, the potentiometer or sensor wiring is the most common point of failure, not the drive itself.
Frequently Asked Questions (FAQ)
Q: What is the “ou” (Over Voltage) fault on deceleration?
A: The VFD-EL-W has a small internal braking capacity. If you stop a high-inertia load (like a fan) too quickly, the energy flows back into the drive.
- Increase the Deceleration Time (Parameter 01.10).
- If the application requires fast stopping, the EL-W may not be suitable; consider upgrading to the MS300 which supports external braking resistors better.
Q: How do I reset a Delta VFD-EL-W fault?
A:
- Press the STOP/RESET button on the keypad.
- Toggle the Digital Input (MI1-MI4) if configured for “Reset” (Function 05).
- Power cycle the unit (unplug and wait 30 seconds).
Q: Why does the drive show “oL” (Overload) on a small pump?
A: The EL-W protection curve is sensitive.
- Check if the pump is clogged or the bearing is seized.
- Ensure the Motor Rated Current (Parameter 07.00) is set correctly. If left at factory default, it might not match your motor.
- Check the Torque Boost setting; if too high, it can cause over-current at low speeds.
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