INVT SPC Series Drive Fault Codes List (2026) – Complete reference list of INVT SPC Series (IP65 Solar Pump) fault codes. Learn to troubleshoot weak light alarms (A-LS), tank full warnings (A-tF), and GPRS monitoring issues.
The INVT SPC Series is a specialized Solar Pump Controller designed for harsh outdoor environments. With its IP65 rating, it is often installed directly near the solar array without an additional cabinet. It features advanced MPPT (Maximum Power Point Tracking) and optional GPRS monitoring, meaning many “codes” you see are actually status updates rather than failures.
This guide provides the most updated reference data for 2026 to help you distinguish between normal solar sleep modes (like Weak Light) and critical isolation or hardware faults.
INVT SPC Series Fault Codes Reference Table
Use the search bar in the table below to quickly find your specific error code.
| Fault Code and Meaning | Cause and Remedy |
|---|---|
| OV1 Overvoltage during ACC | Cause: The input voltage is abnormal; There is large energy feedback; No braking components; Energy-consumption braking is not enabled. Remedy:
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| OV2 Overvoltage during DEC | Cause: The input voltage is abnormal; There is large energy feedback; No braking components; Energy-consumption braking is not enabled. Remedy:
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| OV3 Overvoltage during constant speed running | Cause: The input voltage is abnormal; There is large energy feedback; No braking components; Energy-consumption braking is not enabled. Remedy:
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| OC1 Overcurrent during ACC | Cause: The acceleration or deceleration is too fast; The voltage of the grid is too low; The power of the inverter is too low; The load transients or is abnormal; There is to-ground short circuit or output phase loss; There is strong external interference; The overvoltage stall protection is not enabled. Remedy:
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| OC2 Overcurrent during DEC | Cause: The acceleration or deceleration is too fast; The voltage of the grid is too low; The power of the inverter is too low; The load transients or is abnormal; There is to-ground short circuit or output phase loss; There is strong external interference; The overvoltage stall protection is not enabled. Remedy:
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| OC3 Overcurrent during constant speed running | Cause: The acceleration or deceleration is too fast; The voltage of the grid is too low; The power of the inverter is too low; The load transients or is abnormal; There is to-ground short circuit or output phase loss; There is strong external interference; The overvoltage stall protection is not enabled. Remedy:
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| UV Bus undervoltage fault | Cause: The voltage of the grid is too low; The overvoltage stall protection is not enabled. Remedy:
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| OL1 Motor overload | Cause: The grid voltage is too low; The motor rated current is set incorrectly; The motor stall occurs or the load transient is too large. Remedy:
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| OL2 Inverter overload | Cause: The ACC is too fast; The rotating motor is reset; The grid voltage is too low; The load is too heavy; The motor power is too small. Remedy:
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| SPO Phase loss on output side | Cause: Phase loss output occurs to U, V, W (or the three phases of the load are seriously asymmetrical). Remedy:
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| OH2 Inverter module overheat | Cause: Air duct jam or fan damage occurs; Ambient temperature is too high; The time of overload running is too long. Remedy:
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| EF External fault | Cause: SI external faulty input terminal action. Remedy:
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| CE RS485 communication fault | Cause: The baud rate setting is incorrect; A fault occurs to the communication wiring; The communication address is incorrect; There is strong interference to the communication. Remedy:
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| ItE Current detection fault | Cause: The control board connector is in poor contact; Hall device is damaged; An exception occurs on the magnifying circuit. Remedy:
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| tE Motor autotuning fault | Cause: The motor capacity does not match the inverter capacity; Motor parameters are not set correctly; The difference between the parameters obtained from autotuning and the standard ones is great; Autotuning timed out. Remedy:
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| EEP EEPROM operation error | Cause: Error in reading or writing control parameters; The EEPROM is damaged. Remedy:
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| END Running time reached | Cause: The actual running time of the inverter is longer than the internal set running time. Remedy:
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| OL3 Electronic overload fault | Cause: The inverter reports overload pre-alarm according to the setting. Remedy:
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| ETH1 To-ground short-circuit fault 1 | Cause: The output of the inverter is short circuited to the ground; There is a fault in the current detection circuit. Remedy:
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| ETH2 To-ground short-circuit fault 2 | Cause: The output of the inverter is short circuited to the ground; There is a fault in the current detection circuit. Remedy:
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| dEu Speed deviation fault | Cause: The load is too heavy or stalled. Remedy:
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| STo Mal-adjustment fault | Cause: SM control parameters are set incorrectly; Autotuned parameters are not accurate; The inverter is not connected to the motor. Remedy:
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| LL Electronic underload fault | Cause: The inverter reports underload pre-alarm according to the setting. Remedy:
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| A-LS Weak-light pre-alarm | Cause: The sunlight is weak or the PV module configuration is insufficient. Remedy:
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| A-LL Underload pre-alarm | Cause: The pumping pool has no water. Remedy:
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| A-tF Full-water pre-alarm | Cause: The pumping pool is full. Remedy:
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| A-tL Empty-water pre-alarm | Cause: The pumping pool has no water. Remedy:
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Troubleshooting Outdoor Solar Faults
Because the SPC series operates autonomously in the field, diagnostics often involve environmental checks.
- Alarms vs. Faults: Codes starting with “A-“ (e.g., A-LS, A-tF) are purely operational status indicators. The drive is waiting for sunlight or water levels to change. Do not try to “fix” these; the drive will wake up automatically.
- Isolation Faults (E007 / Riso): Since solar panels are exposed to rain and humidity, “Low Insulation Resistance” is common. This means current is leaking from the PV array to the ground frame.
Check: Inspect MC4 connectors for moisture ingress and check cables for rodent damage. - Remote GPRS Monitoring: If the keypad is inaccessible (mounted high up), use the INVT Solar App. The SPC series supports a plug-in GPRS/4G module that pushes real-time fault history (P07 group) to the cloud.
Frequently Asked Questions (FAQ)
Q: The screen says “A-LS”. Is the pump broken?
A: No. A-LS stands for Low Sunshine (Weak Light).
Meaning: The solar voltage is too low to drive the pump (early morning, evening, or heavy clouds).
Action: None required. The SPC controller will automatically restart when the PV voltage rises above the start threshold.
Q: What does “A-tF” or “A-LL” mean?
A: These are water level logic codes:
A-tF (Tank Full): The destination tank is full (Float switch signal active). The pump stops to save water.
A-LL (Load Low / Dry Run): The well is empty. The pump stops to prevent mechanical damage and will retry after a set timer.
Q: How do I fix “E004” (Boost Fail) or “E005” (Grid OC)?
A:
E004: Internal voltage boost circuit failure (often on lower power models). This is a hardware failure requiring repair.
E005: AC Overcurrent. Check if the pump is jammed with sand or if the output cable has a short circuit.