What does error 40 mean on a Voltronic inverter?

40 means: Inv R Short. Output short circuited.

How do I clear or fix error 40?

1. Check if wiring is connected well and remove abnormal load.

Inv R Short

Fault — the inverter cuts its output and the red LED stays solid until the fault is cleared.

InverterFault

Inv R Short — Fault code 40 shown on the display with the fault icon on: Inv R Short.

Cause: Output short circuited.

Source: InfiniSolar-TX-PA_manual.pdf, p.51

What does error 40 mean on a Voltronic inverter?: 40 means: Inv R Short. Output short circuited.
Is error 40 a fault or a warning?: 40 is a fault code: the inverter cuts its output and the red LED stays solid until it is cleared.
How do I clear or fix error 40?: 1. Check if wiring is connected well and remove abnormal load.

Compiled from official Voltronic user manuals. Always consult your device manual and a qualified technician before performing repairs.