What Does This Error Mean?

Advice UPS in bypass mode means connected equipment is running directly from mains power with no battery backup and no power conditioning. Bypass is triggered automatically when the UPS detects a fault, overload, or overheating that prevents normal operation.

Affected Models

Advice UPS Line-Interactive Series
Advice UPS Online Series
Advice UPS (all models)

Common Causes

Overload — load exceeded the UPS capacity so it switched to bypass to avoid shutdown
UPS overheating — thermal protection triggered bypass mode
Battery fault — battery is too degraded for the UPS to risk running from it
Manual bypass enabled for maintenance — user-activated bypass switch left on
UPS fault — inverter or charger failure causing automatic bypass

How to Fix It

Check the front panel for a fault code.

In bypass mode, Advice UPS models usually show a specific fault code or indicator alongside the 'Bypass' status. Note any displayed codes and refer to the manual — this identifies whether bypass was triggered by overload, temperature, or a battery fault.
Reduce the load and allow cooling.

Disconnect non-essential devices from the UPS. If overheating triggered bypass, move the UPS to a well-ventilated area with at least 20cm clearance on all sides. Wait 15–20 minutes for the unit to cool before attempting to restore normal mode.
Check for a manual bypass switch.

Some Advice UPS models have a physical bypass switch or button for maintenance use. Verify that no manual bypass has been activated — check all switches on the front and rear panels. If a manual bypass was activated, switch it back to normal mode.
Restart the UPS.

Power off the UPS by holding the power button. Wait 30 seconds with no load connected. Power on again. If the UPS starts in normal mode (not bypass), the triggering condition has been resolved. Reconnect loads gradually.
Check battery health.

A failed battery can force the UPS into bypass because it cannot operate the inverter without a functional battery. Note when the battery was last replaced — sealed lead-acid batteries should be replaced every 3–5 years. If battery is due for replacement, install a new one and test if normal mode is restored.

When to Call a Professional

If bypass mode cannot be cleared after resolving overload and temperature issues, and the UPS is not in maintenance bypass, the inverter circuit has likely failed. Contact Advice support.