For an OV-DC alarm, first check the DC voltage at the inverter test points with the DC switch off. If the reading is high, check the string configuration. Next, turn the DC switch on and compare your reading with the inverter LCD. If the two disagree, the inverter's measurement circuit may be bad and the inverter may need replacing. For OV-BUS and UN-BUS bus voltage alarms, measure both DC and AC voltages and compare them with the LCD. Possible causes are internal damage or a wire that came loose during shipping. To verify the DC configuration, note how many panels are in each string and record the string voltage. Inverter-level measurements of DC input voltage are typically accurate to within ±2%, so treat small differences with care. Safety: on units with the automatic PID function, the PID module applies 450 Vdc between PV negative and ground when the DC bus voltage drops below 50 Vdc.
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producesc1 verified · fact High DC input voltage
Measured at the inverter test points with the DC switch off; a high reading points to the string configuration.
tbl=14.r3 h=4bc70d0f58e4tbl=14 h=050063b1c3a4verified by: review-workflowverified on: 2026-10-23
c2 drafted · lead Meter vs display mismatch
When the meter reading differs from the inverter LCD value, the inverter's measurement circuit may be faulty. Applies to OV-DC, OV-BUS and UN-BUS.
Check LCD reading, may be a bad measurement circuit
tbl=13.r5 h=7868f947bd08tbl=14.r3 h=4bc70d0f58e4tbl=14.r4 h=980abe97f48ctbl=14 h=050063b1c3a4review note: review: partial - Only OV-DC links the LCD reading to a possible bad measurement circuit; OV-BUS and UN-BUS just say to compare with the LCD and replace the inverter, so the note's 'applies to OV-DC, OV-BUS and UN-BUS' scope goes beyond the passages.
c3 verified · fact Zero DC voltage reading
If the DC voltage reads zero with the DC switch on, the guidance is to replace the inverter.
tbl=13 h=e3da18e1612cverified by: review-workflowverified on: 2026-10-23
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