MuscleGrid Heavy Duty Series (3.6–6.2 kW) — All Fault Codes

01Fault 01: Fan is locked (when inverter is off), or fan fault

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 01 — Fan is locked (when inverter is off), or fan fault. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 01. What to do: Replace the fan; ensure it spins freely and is connected.

02Fault 02: Over temperature, or NTC not connected well

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 02 — Over temperature, or NTC not connected well. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 02. What to do: Internal component temp over 100–120 °C — check the unit's airflow isn't blocked and ambient isn't too hot; let it cool.

03Fault 03: Battery voltage is too high (battery over-charged)

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 03 — Battery voltage is too high (battery over-charged). This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 03. What to do: Check battery type/quantity match the unit's spec; if it persists, return to the repair center.

04Fault 04: Battery voltage is too low

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 04 — Battery voltage is too low. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 04. What to do: Re-charge the battery; if it won't hold charge, replace it.

05Fault 05: Output short-circuited, or over-temperature detected by internal converter components

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 05 — Output short-circuited, or over-temperature detected by internal converter components. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 05. What to do: Check output wiring and remove any shorted/abnormal load; ensure airflow isn't blocked.

06Fault 06: Output voltage is too high

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 06 — Output voltage is too high. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 06. What to do: Output abnormal (<190 V or >260 VAC): reduce the connected load; if it persists, return to repair.

07Fault 07: Overload time-out

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 07 — Overload time-out. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 07. What to do: Inverter overloaded (>105–110%) and time elapsed: switch off some equipment to reduce load. If caused by high PV derating, reduce PV modules in series.

08Fault 08: Bus voltage is too high

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 08 — Bus voltage is too high. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 08. What to do: Internal components fault — return to the repair center.

09Fault 09: Bus soft-start failed

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 09 — Bus soft-start failed. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 09. What to do: Internal components fault — return to the repair center.

51Fault 51: Over current or surge

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 51 — Over current or surge. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 51. What to do: Restart the unit; if the error recurs, return to the repair center.

52Fault 52: Bus voltage is too low

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 52 — Bus voltage is too low. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 52. What to do: Internal fault — return to the repair center.

53Fault 53: Inverter soft-start failed

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 53 — Inverter soft-start failed. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 53. What to do: Internal components fault — return to the repair center.

55Fault 55: Over DC voltage in AC output (output voltage unbalanced)

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 55 — Over DC voltage in AC output (output voltage unbalanced). This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 55. What to do: Return to the repair center.

57Fault 57: Current sensor failed

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 57 — Current sensor failed. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 57. What to do: Internal components fault — return to the repair center.

58Fault 58: Output voltage is too low

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 58 — Output voltage is too low. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 58. What to do: Output abnormal (<190 V or >260 VAC): reduce the connected load; if it persists, return to repair.

59Fault 59: PV voltage is over the limitation

Heavy Duty Series (3.6–6.2kW) (heavy_duty) FAULT CODE 59 — PV voltage is over the limitation. This is a FAULT: steady red Fault LED, the inverter STOPS and the LCD shows fault code 59. What to do: Reduce the number of PV modules in series so PV input is within spec.

01Warning 01: Fan is locked when inverter is on

Heavy Duty Series (3.6–6.2kW) (heavy_duty) WARNING/ALARM CODE 01 — Fan is locked when inverter is on. This is a WARNING (not a fault): red LED FLASHES, the inverter KEEPS RUNNING. Audible: Beeps 3× every second. What to do: Check the cooling fan is connected and spinning.

02Warning 02: Over temperature

Heavy Duty Series (3.6–6.2kW) (heavy_duty) WARNING/ALARM CODE 02 — Over temperature. This is a WARNING (not a fault): red LED FLASHES, the inverter KEEPS RUNNING. Audible: None. What to do: Reduce load; ensure airflow isn't blocked and ambient isn't too hot.

03Warning 03: Battery is over-charged

Heavy Duty Series (3.6–6.2kW) (heavy_duty) WARNING/ALARM CODE 03 — Battery is over-charged. This is a WARNING (not a fault): red LED FLASHES, the inverter KEEPS RUNNING. Audible: Beeps once every second. What to do: Check the charging settings / battery spec.

04Warning 04: Low battery

Heavy Duty Series (3.6–6.2kW) (heavy_duty) WARNING/ALARM CODE 04 — Low battery. This is a WARNING (not a fault): red LED FLASHES, the inverter KEEPS RUNNING. Audible: Beeps once every second. What to do: Re-charge the battery, or restore mains/PV to charge it.

07Warning 07: Overload

Heavy Duty Series (3.6–6.2kW) (heavy_duty) WARNING/ALARM CODE 07 — Overload. This is a WARNING (not a fault): red LED FLASHES, the inverter KEEPS RUNNING. Audible: Beeps once every 0.5 second. What to do: Reduce the connected load by switching off some equipment.

10Warning 10: Output power derating

Heavy Duty Series (3.6–6.2kW) (heavy_duty) WARNING/ALARM CODE 10 — Output power derating. This is a WARNING (not a fault): red LED FLASHES, the inverter KEEPS RUNNING. Audible: Beeps 2× every 3 seconds. What to do: Informational — output is being derated (e.g. high PV/temperature).

15Warning 15: PV energy is low

Heavy Duty Series (3.6–6.2kW) (heavy_duty) WARNING/ALARM CODE 15 — PV energy is low. This is a WARNING (not a fault): red LED FLASHES, the inverter KEEPS RUNNING. Audible: Beeps 2× every 3 seconds. What to do: Informational — insufficient solar; normal at low light.

16Warning 16: High AC input (>280 VAC) during BUS soft start

Heavy Duty Series (3.6–6.2kW) (heavy_duty) WARNING/ALARM CODE 16 — High AC input (>280 VAC) during BUS soft start. This is a WARNING (not a fault): red LED FLASHES, the inverter KEEPS RUNNING. Audible: None. What to do: Check the incoming mains/generator voltage is within range.

Warning E9: Battery equalization in progress

Heavy Duty Series (3.6–6.2kW) (heavy_duty) WARNING/ALARM CODE E9 — Battery equalization in progress. This is a WARNING (not a fault): red LED FLASHES, the inverter KEEPS RUNNING. Audible: None. What to do: Informational — equalization charging is running (lead-acid only).

Warning bP: Battery is not connected

Heavy Duty Series (3.6–6.2kW) (heavy_duty) WARNING/ALARM CODE bP — Battery is not connected. This is a WARNING (not a fault): red LED FLASHES, the inverter KEEPS RUNNING. Audible: None. What to do: Check the battery wiring/connection.

BMS code 60

Heavy Duty Series (3.6–6.2kW) (heavy_duty) BMS CODE 60 — After a successful BMS handshake, the battery is not allowed to charge OR discharge — the inverter stops both. An informational LCD code shown for lithium batteries after a successful BMS handshake. The lithium battery's BMS is protecting itself; check the battery state / BMS and let it recover.

BMS code 61

Heavy Duty Series (3.6–6.2kW) (heavy_duty) BMS CODE 61 — Communication lost with the battery BMS (no signal for 1 min when not connected, or comms dropped after a successful connect — buzzer beeps). An informational LCD code shown for lithium batteries after a successful BMS handshake. Check the BMS communication cable (RS485/CAN) between battery and inverter.

BMS code 62

Heavy Duty Series (3.6–6.2kW) (heavy_duty) BMS CODE 62 — After a successful BMS handshake, the battery is not allowed to charge — charging stops. An informational LCD code shown for lithium batteries after a successful BMS handshake. BMS is blocking charge (e.g. full / protection); informational, recovers on its own.

BMS code 70

Heavy Duty Series (3.6–6.2kW) (heavy_duty) BMS CODE 70 — After a successful BMS handshake, the battery requests charging — the inverter charges. An informational LCD code shown for lithium batteries after a successful BMS handshake. Informational — normal BMS-requested charge.

BMS code 71

Heavy Duty Series (3.6–6.2kW) (heavy_duty) BMS CODE 71 — After a successful BMS handshake, the battery is not allowed to discharge — discharge stops. An informational LCD code shown for lithium batteries after a successful BMS handshake. BMS is blocking discharge (e.g. low SOC / protection); recovers when the BMS permits.

Troubleshooting

Heavy Duty Series (3.6–6.2kW) (heavy_duty) TROUBLESHOOTING. Unit shuts down during startup (LCD/LEDs/buzzer on for 3 s then fully off): Battery voltage is low (<1.91 V/cell). Re-charge the battery; replace if it won't hold. | No response at all after power-on: Battery far too low (<1.4 V/cell) or the internal fuse tripped. Contact the repair center to replace the fuse; re-charge or replace the battery. | Mains present but unit runs on battery (green LED flashing): Poor AC quality, OR AC wires too thin/long, OR wrong input-voltage-range setting, OR output priority is set to 'Solar First'. Check wiring/setting; set output priority to 'Utility First' if you want grid first. | Internal relay clicks on/off repeatedly (LCD/LEDs flashing): Battery is disconnected — check the battery wires are connected well.

Settings: Output & input

Heavy Duty Series (3.6–6.2kW) (heavy_duty) LCD SETTING — Output & input. Enter setup: press & hold ENTER 3 s; UP/DOWN to select a program; ENTER to confirm; ESC to exit. 00 Exit setting mode: 'GOE' escape(default) / 'GOH' one-button restore settings. 01 Output source priority: 'USb' Utility first / 'SUb' Solar first(default) / 'SbU' SBU (utility only when battery drops to the low-voltage warning or program-12 point). 02 Max total charging current: default 60 A, 10 A–140 A (130/140 A on 7.2 kW), 10 A steps. 03 AC input voltage range 'APL'(90–280 VAC, default)/'UPS'(170–280 VAC). 09 Output frequency 50 Hz(default)/60 Hz. 10 Output voltage 220/230(default)/240 V. (HD has no ECO program 08.)

Settings: Battery type & charger priority

Heavy Duty Series (3.6–6.2kW) (heavy_duty) LCD SETTING — Battery type & charger priority. 05 Battery type: AGM(default) / FLd Flooded / USE User-Defined / LIb lithium (set to LIB for a lithium battery; activates after 3 s). 16 Charger source priority: 'CSO' Solar first / 'SNU' Solar+Utility(default) / 'OSO' Only Solar. In battery/power-saving mode only solar charges. 11 Max utility charging current default 30 A [2 A,10–100 A].

Settings: Charging voltages (by model)

Heavy Duty Series (3.6–6.2kW) (heavy_duty) LCD SETTING — Charging voltages (by model). Model tiers: 3.6 kW = 24 V system; 6.2/7.2 kW = 48 V system. 26 Bulk/CV charge: 3.6 kW default 28.2 V [25.0–29.0 V]; 6.2/7.2 kW default 56.4 V [48.0–58.0 V]; 0.1 V steps (User-Defined only). 27 Float charge: 3.6 kW default 27.0 V; 6.2/7.2 kW default 54.0 V (same ranges). 29 Low DC cut-off: 3.6 kW default 20.0 V [20.0–24.0 V]; 6.2/7.2 kW default 40.0 V [40.0–48.0 V]. CV must be higher than float.

Settings: Battery switch thresholds & alarms

Heavy Duty Series (3.6–6.2kW) (heavy_duty) LCD SETTING — Battery switch thresholds & alarms. 12 Voltage point back to utility (SBU/Solar-first): 3.6 kW default 23.0 V [21.0–25.5 V]; 6.2/7.2 kW default 46 V [42–51 V]. 13 Voltage point back to battery (SBU/Solar-first): 3.6 kW 'FUL'/27.0 V [24–29 V]; 6.2/7.2 kW 'FUL'/54.0 V [48–58 V]. 18 Alarm control bON(default)/bOF. 22 Beeps when primary source interrupted AON(default)/AOF. 23 Overload bypass byd(default)/byE. 25 Record fault code FEN(default)/FdS. 19 Auto-return display ESP(default)/tEP. 20 Backlight LON(default)/LOF.

Settings: Battery equalization (lead-acid only)

Heavy Duty Series (3.6–6.2kW) (heavy_duty) LCD SETTING — Battery equalization (lead-acid only). Only when Flooded or User-Defined in program 05. 30 Equalization EEn / EdS(default). 31 Equalization voltage: 3.6 kW default 29.2 V [25.0–31.5 V]; 6.2/7.2 kW default 58.4 V [48.0–61.0 V]. 33 Equalized time 60 min [5–900]. 34 Equalized timeout 120 min [5–900]. 35 Equalization interval 30 days [0–90]. 36 Equalize immediately AEn/AdS(default) (LCD shows 'E9'). Do NOT equalize lithium batteries.

Settings: Grid-tie & dual output

Heavy Duty Series (3.6–6.2kW) (heavy_duty) LCD SETTING — Grid-tie & dual output. 37 Grid-tie operation: 'OFF' off-grid(default, solar→loads then charge) / 'HYd' hybrid (solar→loads, charge, excess feeds to grid). 38 Grid-tie current 10 A (2 A steps). 39 LED pattern light LOF/LON(default). 41 Dual output L2F disable(default)/L2O use. 42 Dual-output functional voltage point: 3.6 kW(24 V) default 22.0 V [20.0–23.0 V]; 6.2/7.2 kW(48 V) default 44.0 V [40.0–46.0 V]; 0.1 V steps.