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← Fault codes
Hybrid inverter

Sol-Ark 15K-2P-N

Sol-Ark prefixes every code with F, and several of them are notifications rather than faults. If the system faults five times in a row it stops completely and needs a manual restart.

Faults — the unit stops (25)
F8. Fault. Do not just reset. GFDI relay failure. Leakage from the AC output to ground, or a neutral-ground bonding problem.
Check first
  1. Check continuity between the inverter's neutral and ground.
  2. There must be exactly ONE neutral-to-ground bond in the whole system, at the main panel.
  3. A portable generator with its own bond is a classic cause.
F15. Fault. AC overcurrent. Usually loads too large for the inverter.
Check first
  1. Reduce load. Off-grid, check that battery discharge amps are not programmed too low.
  2. Overloads commonly cascade into F15, F18, F20, or F26 together.
F16. Fault. Do not just reset. GFCI failure. A ground fault on the DC side.
Check first
  1. Check PV+ and PV− wiring. Both must be ungrounded.
  2. Exposed conductors plus rain will do this.
  3. Verify neutral and ground are not double-bonded — common with portable generators.
F18. Fault. AC overcurrent (Tz). The load output or a generator was overloaded, or there is a short on the AC side.
Check first
  1. Reduce loads, or reduce Gen Start A.
  2. Ring out the AC side for a short.
  3. Often appears together with F15, F20, F26.
F20. Fault. Do not just reset. DC overcurrent (Tz). Too much DC current from the battery, or too much PV current.
Check first
  1. A large motor load such as a 4-ton AC unit is a typical cause.
  2. Three or more strings paralleled on one MPPT will do it.
  3. A grounded PV conductor can cause F20, F23, or F26.
F24. Fault. Do not just reset. DC insulation fault. An exposed PV conductor plus moisture is faulting.
Check first
  1. Do not reset and walk away. Find the damaged conductor.
  2. Can appear together with F16 and F26.
  3. Check for pinched wire under rails and water in junction boxes.
F25. Fault. DC feedback fault. No battery is connected but 'Activate Battery' is enabled. NOTE: unrelated to EG4 code 25, which is over-temperature.
Check first
  1. Disable 'Activate Battery' in settings while no battery is connected.
  2. Power cycle after changing battery mode.
F26. Fault. Do not just reset. Bus unbalance. Too much load on one leg versus the other, or DC loads on the AC output when off-grid.
Check first
  1. Balance L1 and L2 loads across the essential loads panel.
  2. A grounded PV conductor can also cause this.
  3. Check the phase sequence between GRID and LOAD terminals.
F29. Fault. Parallel CANBus fault. Communication error between parallel inverters.
Check first
  1. Check the parallel cables and the Modbus addresses.
  2. Sol-Ark notes F29 and F41 are expected briefly during parallel startup until all units are on.
F31. Fault. Soft start failed on a large motor.
Check first
  1. The motor's inrush exceeded what the inverter could ramp. Add a soft start to the compressor.
F34. Fault. AC overload, or the load is shorted.
Check first
  1. Reduce heavy loads. Check the transfer switch and subpanel wiring for a short.
F37. Fault. DCLLC software overcurrent.
Check first
  1. Restart. Persistent means the unit needs service.
F39. Fault. DCLLC hardware overcurrent.
Check first
  1. Restart. Repeated hardware overcurrent trips mean the unit goes back.
F40. Fault. Battery over current. The bank exceeded its programmed discharge limit.
Check first
  1. Check Max A Discharge against the battery manufacturer's rating.
  2. Off-grid, the bank discharges to 120% of this value for ten seconds before faulting.
F45. Fault. Grid under voltage caused a disconnect.
Check first
  1. Self-resets when the grid stabilizes. Persistent means a utility or service conductor problem.
F46. Fault. Battery backup fault. Cannot communicate with the other parallel systems.
Check first
  1. Master must be Modbus SN 1, slaves 2 through 9.
  2. Check that the parallel Ethernet cables are connected.
F47. Fault. Grid over frequency caused a disconnect.
Check first
  1. Common during outages. Self-resets when the grid stabilizes. On a generator, widen the frequency window.
F48. Fault. Grid under frequency caused a disconnect.
Check first
  1. Common during outages. Self-resets. On a generator, widen the frequency window.
F55. Fault. Do not just reset. DC voltage high. PV may be above 500 V, or battery voltage is above the limit.
Check first
  1. Open the PV disconnect and measure Voc cold. 500 VDC is the hard ceiling on any MPPT.
  2. Battery should not exceed 59 V or 63 V depending on model.
  3. Exceeding 500 Voc causes damage, not just a fault.
F56. Fault. Do not just reset. DC voltage low. Batteries over-discharged, off-grid discharge current exceeded by 20%, or the lithium BMS shut down.
Check first
  1. Measure the pack. Check whether the BMS has opened.
  2. Verify the battery settings — wrong parameters alone can cause this.
F58. Fault. BMS communication fault. The inverter is set to BMS Lithium mode but cannot reach a BMS.
Check first
  1. Check the RJ45 in the Battery CANBus port. CAN Hi is pin 4, CAN Lo is pin 5.
  2. Verify the battery appears on Sol-Ark's battery-partners list.
  3. BMS_Err_Stop is enabled and will stop the system on comm loss.
F60. Fault. Generator voltage or frequency went outside the allowable range.
Check first
  1. Set Grid Mode to General Standard, widen frequency to 55–65 Hz and voltage to 185–275 V.
  2. Generator THD should be under 15%.
F61. Fault. Button manual off. A parallel slave was turned off without turning off the master.
Check first
  1. Power the group down in the correct order: masters first, then slaves. Bring slaves up first, master last.
F63. Fault. Do not just reset. Arc fault detected on the DC side.
Check first
  1. Inspect every PV connector before clearing. A poor connection is the usual cause.
  2. Sol-Ark notes a powerful lightning storm can trigger a false alarm — but assume it is real until you have looked.
  3. The fault must be cleared manually: Basic Setup, Advanced, Clear Arc Fault.
F64. Fault. Heatsink high temperature.
Check first
  1. Check that the built-in fans are running.
  2. Verify at least 6 in of vertical and 2 in of side clearance.
  3. Ambient may simply be too high — the LCD derates at 75 °C and shuts down at 82 °C.
Status — not a problem (5)
F1. Status. DC inversed. In a parallel system, turning one unit off raises this on the others. Sol-Ark states this is a notification, not a fault.
Check first
  1. Expected when you power down one inverter in a parallel group. No action.
F13. Status. Grid mode change. Raised when running without batteries or when grid input settings change. Sol-Ark states this is a notification, not a fault.
Check first
  1. If you switched from No Batt to Battery mode, power down completely and restart.
F22. Status. Emergency stop was initiated.
Check first
  1. Check the E-Stop contact on the B/B pins. This is the system doing its job.
F35. Status. AC no utility. Grid connection lost.
Check first
  1. Expected during an outage. If the grid is up, check the GRID breaker and the external disconnect.
F41. Status. Parallel system stop. Another inverter in the group faulted and this one disconnected in sympathy.
Check first
  1. Find the unit that faulted first. This code is the symptom, not the cause.
  2. Expected briefly during parallel startup.
Source: Sol-Ark 15K-2P-N Installation Guide, SK140-0001 Rev. 5, section 8.1. Firmware and manual revisions change these tables. Confirm against the manual for the unit in front of you before you act.