Solar Tool Pro
Offline ready
← Fault codes
Off-grid inverter

EG4 6000XP Off-Grid

Watch the face icon on the LCD before you read the number. A sad face means a fault; a neutral face means a warning; a smiling face means it is a status code. The same two digits appear in all three tables and mean different things - code 00 is a battery comms warning but an internal comms fault.

Faults — the unit stops (21)
00. Fault. Internal communication fault. The Comm CPU lost data from the Control CPU. NOT the same as warning 00.
Check first
  1. This is the fault table, not the warning table. Warning 00 is a battery comms failure — check which icon the LCD is showing: sad face is a fault, neutral face is a warning.
  2. Confirm the last firmware update completed.
  3. Update to the latest firmware, then restart.
02. Fault. Do not just reset. Bat On Mos fail. Reverse battery connection damaged the anti-reverse MOSFET, or the sampling circuit failed.
Check first
  1. Verify battery polarity before you power anything back up.
  2. Restart. If it persists the unit is damaged and needs the distributor.
03. Fault. CT fail. Internal CT offset error in the control program.
Check first
  1. Update firmware, then restart.
08. Fault. CAN communication error in a parallel system.
Check first
  1. If it is not actually a parallel system, set 'No Parallel'.
  2. Use a straight-through Cat 5 cable.
  3. Check the DIP switch configuration against the parallel guide.
09. Fault. No master in the parallel system.
Check first
  1. Exactly one inverter is Master. Check the Master/Slave setting on every unit, then restart.
12. Fault. Do not just reset. UPS output short circuit while running off-grid.
Check first
  1. Power down first.
  2. Ring out the load side for a short.
  3. Check whether L and N have been reversed on one of the inverters.
13. Fault. UPS reverse current. Reverse power in a parallel system exceeded the limit.
Check first
  1. If the units are set 'No Parallel' but wired in parallel, set them to single-phase parallel.
  2. Verify the Cat 5 parallel cable and DIP switches.
  3. On a single inverter, confirm the application setting is 'No Parallel'.
  4. Load port wiring must be consistent across all units.
15. Fault. Phase error in a three-phase system, or a phase is missing.
Check first
  1. If it is not a three-phase parallel system, set single-phase parallel or no parallel.
  2. Check L and N connections and breaker states.
16. Fault. Relay fault. An internal relay failed its self-test.
Check first
  1. Restart once. A relay that will not pass self-test is a return, not a repair.
17. Fault. Internal communication fault 2. Bus1 is above 150 V and the MPPT board is running, but the Comm board sees no valid MPPT data.
Check first
  1. Check that Comm and MPPT firmware are both current.
  2. Power switch off, wait three minutes, restart.
18. Fault. Internal communication fault 3. The Control board is not receiving valid data from the Comm board.
Check first
  1. Verify Comm and DSP firmware are both up to date.
  2. Power off three minutes, restart.
19. Fault. Do not just reset. Bus voltage too high. Bus1 or Bus2 is out of range.
Check first
  1. Measure PV input. Anything over 480 VDC is out of spec — reduce modules per string.
  2. Correct Voc to the site's record low before you rebuild the string.
  3. Update firmware.
20. Fault. Do not just reset. AC connection fault. The AC input was landed on the EPS/LOAD port, or on the GEN port in AC-couple or smart-load mode.
Check first
  1. Trace the terminals before re-energizing. Grid feeds GRID.
  2. Getting this backwards can energize the wrong side of the system.
21. Fault. Do not just reset. PV voltage too high. PV1 or PV2 exceeded 480 VDC. This is the fault that kills inverters.
Check first
  1. Open the PV disconnect first.
  2. Measure Voc on every string with the array cold.
  3. Recalculate maximum modules per string against the record low temperature. A string that is legal at noon can be illegal at sunrise.
22. Fault. Over current internal. Hardware-level overcurrent protection tripped.
Check first
  1. Power switch off, wait three minutes, restart. Repeated hardware trips mean the unit goes back.
24. Fault. Do not just reset. PV short. Overcurrent protection triggered, or PV input current exceeded 23 A.
Check first
  1. Open the PV input first.
  2. Measure string voltage, then check resistance at the inverter side with a meter.
  3. Ring out each string for a short before reconnecting.
25. Fault. Temperature too high. NTC reads above 92 °C, or the NTC is open and reading −25 °C.
Check first
  1. Check air ducts and vents for blockage.
  2. Reseat the fan cable on the interface board.
  3. Shut down ten minutes and restart. If it faults in standby, the temperature sampling circuit is bad.
26. Fault. Internal fault. Bus1 is 50 V below the PV input, or 50 V below Bus2 — not physically sensible.
Check first
  1. Restart. Persistent means the unit needs service.
28. Fault. Sync signal lost in the parallel system.
Check first
  1. Confirm the parallel cables are in the correct ports.
  2. All inverters in the group must be on the same firmware.
  3. Restart the group.
29. Fault. Sync trigger signal lost in the parallel system.
Check first
  1. Use the T568B Ethernet cable that shipped with the inverter, in the correct ports.
  2. Verify DIP switch configuration.
  3. All units on the same firmware.
31. Fault. Internal communication fault 4. The MPPT board is not receiving valid data from the Comm board.
Check first
  1. Confirm both Comm and MPPT firmware updates completed.
  2. Power off three minutes, restart.
Alarms — it may keep running (20)
00. Alarm. Battery communication failure. No CAN or RS485 data is reaching the inverter.
Check first
  1. Check the RJ45 pinout at both ends. Inverter side: CAN H is pin 4, CAN L is pin 5; RS485 B is pin 1, A is pin 2.
  2. Confirm the cable is in the right port — CAN and RS485 are not interchangeable.
  3. Check the battery DIP switch addresses.
  4. Verify the battery brand is set correctly. For EG4, choose Lithium then brand 1; for LifePower4 V1 or RS485, use 0.
01. Alarm. The inverter cannot reach its AFCI module.
Check first
  1. Restart. If it does not clear, the arc-fault board needs service — and you are running without arc-fault protection.
02. Alarm. Do not just reset. AFCI high. An arc fault was detected on the PV side.
Check first
  1. Do not clear and walk away. Inspect the DC path physically.
  2. Measure Voc and Isc on every string and compare against expected values.
  3. A loose or cross-mated MC4 is the overwhelming cause. Only clear the fault on the LCD after you have found and fixed the connection.
03. Alarm. Meter communication failure.
Check first
  1. Restart. Check the meter cable and that the meter is powered.
04. Alarm. Do not just reset. Battery fault. Comms are fine, but the BMS is refusing to charge or discharge.
Check first
  1. Check the comm cable pinout at both ends.
  2. Confirm a supported battery protocol is selected.
  3. Look at the battery's own fault indicator — if the BMS is faulting, this is a battery problem.
  4. Cold blocks charging on LFP, exactly as it should.
06. Alarm. Rapid shutdown is active.
Check first
  1. Check whether the RSD or E-Stop button is pressed or latched. This is the system doing its job.
08. Alarm. Firmware mismatch between the microprocessors.
Check first
  1. Re-run the update, start to finish, on every inverter in the parallel group.
  2. Shut down properly, wait three minutes, restart.
  3. Never interrupt a firmware update.
09. Alarm. A cooling fan is stuck.
Check first
  1. Kill power and look for debris or a seized bearing.
  2. Reseat the fan cable on the interface board.
  3. A stuck fan becomes fault 25 under load. Fix it before summer.
12. Alarm. Bat on Mos. The reverse-polarity MOSFET is not turning on.
Check first
  1. Shut down properly, wait three minutes, restart. If it persists the unit needs service.
13. Alarm. Over temperature. The NTC is reading above 87 °C.
Check first
  1. Check for a stuck fan and blocked air ducts.
  2. Clean the dust filters.
  3. Reseat the fan cable on the interface board.
15. Alarm. Do not just reset. Bat reverse. The battery is connected backwards.
Check first
  1. Stop. Open the battery disconnect before you do anything else.
  2. Verify positive to BAT+ and negative to BAT−. Cross-polarity damages the unit and voids the warranty.
18. Alarm. AC frequency out of range after the inverter self-adjusted to the grid.
Check first
  1. Measure grid frequency. On a generator, widen the frequency window or fix the governor.
  2. Open the grid input or restart to let it self-adjust again.
19. Alarm. AC inconsistent in a parallel system. The units disagree about grid voltage, frequency, or phase.
Check first
  1. Every inverter in parallel must be fed from one common AC source.
  2. On three-phase, check that the configured phase matches the detected phase on each slave.
20. Alarm. Do not just reset. PV isolation low. The insulation-resistance protection tripped.
Check first
  1. Look for damaged PV conductor insulation and pinched wire under racking.
  2. Check that module frames and racking are properly grounded.
  3. Get conductors out of standing water. This is a shock hazard, not a nuisance trip.
25. Alarm. Do not just reset. Battery voltage high — above 59 V.
Check first
  1. Measure the pack at the terminals.
  2. Check charge voltage settings against the battery manufacturer's numbers.
  3. If the pack is genuinely over 59 V, power it down and disconnect it from the inverter.
26. Alarm. Do not just reset. Battery voltage low — below the cutoff setting or below 40 V.
Check first
  1. Check the low-voltage warning and SOC settings.
  2. Measure the pack. A deeply discharged LFP bank may need the BMS woken before it accepts charge.
27. Alarm. Battery open. The inverter reads under 40 V and cannot see a battery.
Check first
  1. Check the battery breaker and any DC fuse.
  2. Confirm the pack has not shut itself down on its own protection.
28. Alarm. EPS overload. The load output voltage sagged because the load is too big.
Check first
  1. Total what is actually on the LOAD panel. Continuous is 6 kW.
  2. Check whether PV and battery together can even supply it.
  3. Once under 100%, wait ten minutes or cycle the EPS switch.
29. Alarm. EPS voltage high. Off-grid output RMS is more than 30 V above nominal.
Check first
  1. Look for a device causing surges on the load side.
  2. Recovery takes about twenty minutes. Restart if it persists.
31. Alarm. EPS DCV high. Too much DC component on the off-grid output.
Check first
  1. Restart. Persistent means the unit needs service.
Status — not a problem (12)
00. Status. Standby. The inverter is powered but not inverting.
Check first
  1. Normal. If you expected output, check the EPS output switch and that the unit is not left in standby.
02. Status. Firmware update in progress.
Check first
  1. Do not interrupt it. A partial update leaves the processors mismatched and throws warning 08.
08. Status. PV charge. Solar is charging the battery only, capped by the battery's charge power.
Check first
  1. Normal with the EPS switch off. The inverter must not be in standby for this.
10. Status. Battery on-grid. Grid is up, no PV input.
Check first
  1. Normal in AC First mode, or in AC Charge when the charge condition is not met.
11. Status. Bypass. Loads are fed from AC only.
Check first
  1. Happens in standby, in ECO mode, or when the unit is in a fault state. If you did not expect bypass, check for an active fault.
14. Status. PV and battery on-grid. Grid takes the load first.
Check first
  1. Normal for AC First or AC Charge with PV present.
19. Status. PV charge plus bypass. Grid feeds the loads, solar goes only to the battery.
Check first
  1. Normal.
20. Status. AC charge. Grid powers loads and charges the battery at the same time.
Check first
  1. Normal.
40. Status. Battery off-grid. Grid is down, battery carries the load alone.
Check first
  1. Normal during an outage with no sun.
80. Status. PV off-grid. Grid is down, solar carries the load.
Check first
  1. Output follows the sun and can be unstable. Expect flicker under cloud.
88. Status. PV charge off-grid. Solar feeds the load and charges the battery.
Check first
  1. Normal.
C0. Status. PV and battery off-grid. Solar plus battery carry the load.
Check first
  1. Normal. If PV exceeds the load, the surplus charges the battery.
Source: EG4 6000XP user manual, v1.7.2, sections 14.1-14.3. Firmware and manual revisions change these tables. Confirm against the manual for the unit in front of you before you act.