VFI-B Series UPS LED Indicators

Here at Power Inspired we look at the nature of the product queries we receive and improve and update our product information as appropriate. One such regular question we have is the status of the UPS LED indicators on the VFI-B series and asking if this is normal. This article looks at the UPS LED indicators only (not the LCD).

Referring to the diagram above we have 4 LEDs. When you power on the unit these LEDs will come on in sequence. Starting from the bottom we have the inverter LED (green), the battery LED (amber), the bypass LED (amber) and the warning LED (red). The diagram shows the most common LED arrangements and I’ll go through these in turn.

1. Normal

In this mode the UPS is switched on and is delivering power from its inverter. This is the default status when powering the unit on, unless other settings have been enabled.

2. ECO mode

This high efficiency mode effectively changes the UPS topology from an online UPS to an offline UPS. The inverter is switched off, but the UPS is still looking out for any power disturbances. In the event the mains should go out of tolerance the unit will switch back to inverter operation. This is also a normal mode which can be enabled or disabled in the unit settings.

3. Battery Mode.

The unit is operating from battery power. This is usually because the unit is receiving no power but may also be because the input voltage is too high, too low or out of frequency range (eg if powered from a low grade generator). The red warning light will flash every 4 seconds simultaneously with the buzzer sounding. If the frequency increases to every second, the battery LED will also flash and this indicates Low Battery. The unit will shortly turn off.

4. Bypass

This mode is one where mistakes can be made which is why it is disabled by default. Here, in bypass mode, the unit UPS function is switched off but the charger and LCD are still active. There is power at the output, which is why some mistakes are made as the assumption is the UPS is “on”. When the UPS is in bypass mode, should the mains power be cut, the unit will simply switch off. Bypass mode is useful as it allows the UPS to be switched off (for maintenance etc) without losing power to the load. If enabled the UPS will revert to bypass if it detects a fault such as an overload. As such bypass mode is enabled when continuity of power is paramount, however secondary checks should be made to ensure the UPS is “online”.

5. Warning LED

If this LED is permanently illuminated and accompanied by the buzzer sounding the UPS has a fault. A fault code is likely to be displayed on the LCD. If it is flashing other LEDs may be illuminated depending upon the UPS mode. For example, the UPS may detect the battery is not connected and flash every four seconds. Flashing twice per second indicates the UPS is overloaded and at risk of shutting off, or the fans may be blocked.

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