Danfoss VLT 2800 Drive Fault Codes List (2026) – Access the complete 2026 reference guide for the legacy Danfoss VLT 2800 drive. Learn to diagnose Err codes, Alarm 14, and back up parameters via MCT 10 before replacement.
The Danfoss VLT 2800 was the versatile “workhorse” of the 2000s. Although officially discontinued and succeeded by the VLT Midi Drive FC 280, thousands of these compact units remain in operation in 2026. When a failure occurs, the numerical LED display provides a specific code prefixed with “AL” (Alarm), “W” (Warning), or “Err” (Error).
This guide provides the most updated reference for 2026 to help you keep these legacy drives running or extract data for migration.
Danfoss VLT 2800 Fault Codes Reference Table
Use the search bar below or browse the table to identify your specific error code.
| Fault Code and Meaning | Cause and Remedy |
|---|---|
| WARNING/ALARM 2 Live zero fault | Cause: The voltage or current signal on terminal 53 or 60 is below 50% of the preset value in parameter 309 or 315 Terminal, min. scaling. Remedy: Check the signal connections and parameter settings (309 or 315). |
| WARNING/ALARM 4 AC line phase fault | Cause: Missing phase on AC line supply side. This fault is only active in 3-phase AC line. Remedy: Check the supply voltage to the adjustable frequency drive. |
| WARNING 5 Voltage warning high | Cause: The DC bus voltage (VDC) is higher than the Voltage warning high limit. Remedy:
|
| WARNING 6 Voltage warning low | Cause: The DC bus voltage (VDC) is lower than the Voltage warn low limit. Remedy: Check whether the supply voltage matches the rating of the adjustable frequency drive. |
| WARNING/ALARM 7 Overvoltage | Cause: The DC bus voltage (VDC) is higher than the inverter’s Overvoltage limit. Can occur if motor frequency is reduced too quickly. Remedy:
|
| WARNING/ALARM 8 Undervoltage | Cause: The DC bus voltage is lower than the inverter’s Undervoltage limit. Remedy: Check whether the supply voltage fits the adjustable frequency drive (See Technical data). |
| WARNING/ALARM 9 Inverter overload | Cause: Electronic thermal inverter protection indicates that the drive is close to disconnecting due to overloading (output current too high for too long). Remedy: Remove the overload condition to the drive. The drive cannot be reset until the counter is below 90%. |
| WARNING/ALARM 10 Motor overloaded | Cause: The motor is too hot according to the electronic thermal inverter protection. The motor is being overloaded by more than 100% for too long. Remedy: Check that motor parameters 102–106 are set correctly. |
| WARNING/ALARM 11 Motor thermistor | Cause: The motor is too hot or the thermistor/thermistor connection is cut off. Remedy: Check that the PTC thermistor has been correctly connected between terminal 18, 19, 27 or 29 (digital input) and terminal 50 (+10 V supply). |
| WARNING/ALARM 12 Current limit | Cause: The output current is greater than the value in parameter 221 Current Limit I_LIM. Remedy: Check load conditions. The drive will trip after a set period (parameter 409). |
| WARNING/ALARM 13 Overcurrent | Cause: The inverter’s peak current limit (approx. 200% of rated output current) has been exceeded. Remedy: Switch off the drive and check that the motor shaft can be turned and that the motor size fits the drive. |
| ALARM 14 Ground fault | Cause: There is a discharge from the output phases to ground, either in the cable between the drive and the motor, or in the motor. Remedy: Turn off the adjustable frequency drive and remove the ground fault. |
| ALARM 15 Switch mode fault | Cause: Fault in switch mode power supply (internal supply). Remedy: Contact your Danfoss supplier. |
| ALARM 16 Short-circuit | Cause: There is a short-circuit on the motor terminals or in the motor. Remedy: Disconnect the AC line supply to the adjustable frequency drive and remove the short-circuit. |
| WARNING/ALARM 17 Serial communication timeout | Cause: There is no serial communication to the adjustable frequency drive. Remedy: Parameter 513 Bus time interval could possibly be increased. |
| WARNING/ALARM 18 HPFB bus timeout | Cause: There is no serial communication to the adjustable frequency drive’s communication option card. Remedy: Parameter 803 Bus time interval could possibly be increased. |
| WARNING 33 Out of frequency range | Cause: The output frequency has reached Output frequency low limit (parameter 201) or Output frequency high limit (parameter 202). Remedy: Check process regulation/closed loop settings. |
| WARNING/ALARM 34 HPFB communication fault | Cause: Communication fault only occurs in Profibus versions. Remedy: Check Profibus communication. |
| ALARM 35 Inrush fault | Cause: The drive has been connected to the AC line supply too many times within 1 minute. Remedy: Limit the frequency of AC line power cycling. |
| WARNING/ALARM 36 Overtemperature | Cause: Heatsink temperature is above limit (75°C – 85°C or 167°F – 185°F depending on unit). Trip occurs at 92°C – 100°C. Potential causes:
Remedy: Ensure ambient temperature is within limits and check installation conditions (cable length, voltage). |
| ALARM 37 Internal fault number 0 | Cause: Communication fault between control card and BMC2. Remedy: Carry out a power cycle. If fault persists, contact supplier. |
| ALARM 38 Internal fault number 1 | Cause: Flash EEPROM fault on control card. Remedy: Carry out a power cycle. If fault persists, contact supplier. |
| ALARM 39 Internal fault number 2 | Cause: RAM fault on control card. Remedy: Carry out a power cycle. If fault persists, contact supplier. |
| ALARM 40 Internal fault number 3 | Cause: Calibration constant error in EEPROM. Remedy: Carry out a power cycle. If fault persists, contact supplier. |
| ALARM 41 Internal fault number 4 | Cause: Data values error in EEPROM. Remedy: Carry out a power cycle. If fault persists, contact supplier. |
| ALARM 42 Internal fault number 5 | Cause: Fault in motor parameter database. Remedy: Carry out a power cycle. If fault persists, contact supplier. |
| ALARM 43 Internal fault number 6 | Cause: General power card fault. Remedy: Carry out a power cycle. If fault persists, contact supplier. |
| ALARM 44 Internal fault number 7 | Cause: Minimum software version of control card or BMC2. Remedy: Carry out a power cycle. If fault persists, contact supplier. |
| ALARM 45 Internal fault number 8 | Cause: I/O fault (digital input/output, relay or analog input/output). Remedy: When restarting after an alarm 38–45, the drive will display alarm 37. In parameter 615 the actual alarm code can be read. |
| ALARM 50 AMT not possible | Cause: Possibilities:
Remedy: Check motor selection and connection. |
| ALARM 51 AMT Fault re. nameplate data | Cause: There is inconsistency in the registered motor data. Remedy: Check the motor data for the relevant setup. |
| ALARM 52 AMT faulty motor phase | Cause: The motor current in at least one of the motor phases is too low. Remedy: Check motor phases and connections. |
| ALARM 53 AMT motor too small | Cause: The motor used is probably too small for the AMT calculations to be carried out. Remedy: Verify motor size compatibility. |
| ALARM 54 AMT incorrect motor | Cause: AMT cannot be performed on the motor being used. Remedy: Check motor type. |
| ALARM 55 AMT timeout | Cause: The calculations are taking too long, possibly due to noise in the motor cables. Remedy: Check motor cabling and grounding. |
| ALARM 56 AMT warning during AMT | Cause: An adjustable frequency drive warning is given while AMT is being performed. Remedy: Resolve the underlying warning. |
| WARNING 99 Locked | Cause: The control panel functions have been locked via parameter 018. Remedy: Unlock via parameter 018. |
How to Read VLT 2800 Faults via LCP & MCT 10
Since the VLT 2800 is a legacy product, it lacks a USB port or a graphical screen. In 2026, maintaining these requires specific connection methods:
- LCP 2 (Control Panel): The standard display is a simple numerical LED.
- Flashing LED: Indicates a Trip (Alarm). The drive has stopped.
- “Err” Codes: Unlike Alarms, an “Err” code (e.g., Err 99) usually indicates a programming mistake, such as trying to change a parameter that is locked while the motor is running.
- MCT 10 Set-up Software: You can still connect a modern PC to this legacy drive.
- Connection: You must use a USB-to-RS485 converter wired to Terminals 68 (+) and 69 (-).
- Backup Strategy: Since these drives are now past their expected service life, use MCT 10 to upload and save the parameter file (.ssp). This allows you to easily convert the settings to a new FC 280 drive using the “Convert” tool in the software.
Frequently Asked Questions (FAQ)
Q: What is the difference between “Alarm 14” (Earth Fault) and “Alarm 16” (Short Circuit)?
A:
- Alarm 14 (Earth Fault): Current is leaking from the motor phase to the ground. This is common in older motors with degrading insulation or water ingress in the conduit.
- Alarm 16 (Short Circuit): There is a direct short between phases (U, V, W). This often indicates the internal IGBT module of the VLT 2800 has failed catastrophically.
Q: How do I reset a Danfoss VLT 2800 fault?
A:
- Press the Stop/Reset button on the front panel.
- Toggle Terminal 19 (Digital Input) if configured for reset.
- Power cycle the unit. Note: For “Trip Locked” faults (like Alarm 13 Overcurrent), a mains power cycle is mandatory.
Q: Should I repair or replace my VLT 2800 in 2026?
A: Replace. The VLT 2800 is obsolete. Spare parts are scarce and expensive. The Danfoss VLT Midi Drive FC 280 is designed as a mechanically compatible retrofit, often fitting into the same footprint with an adapter plate.
Q: Why does the display show “Err” when I try to change a setting?
A: The drive protects certain parameters while the motor is magnetized. Press the Stop button to halt the motor, then try changing the parameter again.