Internal fault (e.g. relay)

What does 720 mean?

The Fronius Primo GEN24 208-240 inverter has detected an internal fault related to one of its output relays. These relays are crucial for safely connecting and disconnecting the inverter from the grid. A fault here prevents proper grid connection.

• Internal fault (e.g. relay).
• Relay stuck open or closed.
• Control circuit issue for the relay.

Click steps to track your progress.

1. 1

   Perform a full power cycle of the Fronius Primo GEN24 208-240 inverter by sequentially opening the AC circuit breaker and the DC disconnector, waiting, and then reclosing them. This attempts to reset the relay.

2. 2

   Listen carefully during startup for any unusual clicking or lack of clicking sounds from the relays that would normally engage.

3. 3

   Visually inspect the inverter's AC connection area for any signs of damage or loose wiring to the output relays (if accessible by qualified personnel).

4. 4

   Check the AC grid voltage and frequency stability, as unstable grid conditions can sometimes prevent relays from engaging correctly.

5. 5

   If the fault persists, this strongly suggests a mechanical or electrical failure of an internal relay; contact Fronius service for specialized repair.