7. Troubleshooting
7.1. The LED alternates between green and red blinking (bootloader mode)
There can be two reasons for this behaviour:
A firmware update is currently being carried out. Once the firmware update is complete, the energy meter automatically returns to application mode, indicated by a solid green LED.
A firmware update was unsuccessful, or there is no application to start. The energy meter remains in bootloader mode until the application has been installed through a firmware update.
To fix this, perform the firmware update again as outlined in the Firmware Updates chapter.
Note
When the energy meter is in bootloader mode, the only available methods for performing a firmware update are through VictronConnect locally (via Ethernet or WiFi) or remotely using VRM: Remote firmware updates (utilising VE.Can or Ethernet connectivity).
Performing a firmware update via VictronConnect Remote (VC-R) in bootloader mode is impossible.
7.2. Error codes
The VM-3P75CT indicates an error by turning the LED solid red when an error is present. Simultaneously, an error code appears on the GX device, VRM, and VictronConnect.
The following error codes can be displayed:
116 - Calibration data lost
If the unit does not work and error 116 pops up as the active error, the unit is faulty. Contact your dealer for a replacement.
119 - Settings corrupt
The energy meter cannot read its configuration and stopped.
To fix the error, perform a factory reset as described in the Restart and reset to factory defaults chapter.
122 - kWh counters corrupt
To fix this error, reset the kWh counter.
7.3. FAQ
7.3.1. The current value seems abnormally high for the displayed power
The energy meter calculates each phase’s active power (P, in Watts), which is what is shown on the display. Active power is determined by:
Single-phase system:
P = Voltage × Current × Power Factor (cos θ)
Three-phase system:
P = √3 × Voltage × Current × Power Factor (cos θ)
If the power factor is unity (cos θ = 1), the real (active) power equals the apparent power (S), which is simply RMS voltage × RMS current.
In most real-world systems, inductive and/or capacitive loads introduce reactive power. This lowers the power factor, so apparent power (S) becomes higher than active power (P).
In AC systems, it is therefore normal and expected for the apparent power (S) to be higher than the active power (P) whenever the power factor is below 1.
The VM-3P75CT also reports the power factor directly. If the current seems unusually high compared to the power reading, check the displayed power factor: a low value confirms that reactive loads are the cause.
Examples of poor power factor:
Small electronic devices such as USB chargers and LED lighting often have a particularly poor power factor.
Renewable generation devices, on the other hand, are legally required to operate close to unity power factor. This can exaggerate the difference between P and S, since the “good” power factor from generation cancels out, leaving only the “poor” factor from the loads.
Possible solutions:
Use loads with built-in power factor correction (common in modern PC power supplies).
Or consider installing dedicated power factor correction equipment.
7.3.2. The firmware update via the Ethernet connection failed
If you encounter problems updating the VM-3P75CT's firmware via Ethernet, try connecting it to the GX device via VE.Can (see the Ethernet and VE.Can wiring section for details), perform the update again as outlined in the Firmware Updates chapter, and then reconnect via Ethernet.