Is your SolaX inverter showing a red light or displaying fault messages like “SPI Fault”, “Overload Fault”, or “EPS Relay Fault”? Don’t panic—your inverter is doing its job by detecting an issue and shutting down to protect your solar system. But to get your power flowing again, you'll need to understand what the error code actually means.

Please reach out to us anytime on the below methods if you are unsure or would like to book an inspection

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This guide to SolaX inverter error codes is designed to make fault diagnosis simple. Whether it’s a communication error, PV voltage issue, internal sensor failure, or something more complex like a Residual Current Device (RCD) fault, we've compiled all the most common SolaX fault codes and their meanings—so you know exactly what you're dealing with.

From single-phase residential units to hybrid and battery-ready systems, we cover every model range including X1, X3, and hybrid inverters. We’re your local experts for all things SolaX, from diagnosis to full repair.

SPI Fault – SPI Communication Issue

This SolaX error code relates to communication problems within the inverter. Try disconnecting the solar panel array using the DC isolator switch. If your SolaX inverter fault remains unresolved after restarting, it’s time to call a solar expert.

SCI Fault – Internal SCI Communication Fault

An internal SCI communication issue is stopping the inverter from working correctly. Switch off the DC isolator to reset the system. If the SolaX inverter error persists, consult a solar technician.

CAN1 Fault – CAN Communication Fault

This SolaX error code indicates a fault in the communication line between components. Shut down both the DC isolator (for the panels) and the battery isolator. Then, power off the inverter via the AC isolator. Restart the system, and if the fault still shows, contact a solair electrical professional.

PV Config. Fault – PV Array Configuration Error

This SolaX inverter fault appears when the photovoltaic system is not connected properly. Restart your inverter to reset the PV connection. If the issue continues, a Solair technician will need to investigate.

Inv. EEPROM – Internal Memory Fault

A failure has occurred in the inverter’s internal memory chip (EEPROM). This kind of SolaX inverter error usually requires a replacement part and should be inspected by a certified technician.

Relay Fault – Relay Malfunction

Your SolaX inverter has detected a problem with its internal relay switch. Shut down your solar system completely and arrange for a professional inspection.

Sample Fault – Detection Circuit Failure

This fault code indicates that the inverter’s internal detection circuit is not working properly. Avoid DIY fixes—contact a solar expert for diagnosis and repair.

RCD Fault – Residual Current Device Issue

An abnormality has been found in the RCD safety function. Check the impedance of the DC input and AC output. After shutting off the system completely, restart it. If the SolaX error code reappears, seek help from a Solair technician.

Fan1 Fault / Fan2 Fault – Inverter Fan Failure

Your inverter fan isn’t working as expected. Check for dust or debris blocking the fan, but do not open the inverter. Restart the system following the shutdown guide. If the problem persists, call in a professional.

AC HCT Fault – AC Current Sensor Fault

This fault relates to the inverter’s ability to detect AC current. Shut off the DC isolator and restart the system. If the SolaX inverter fault remains, a solar technician should inspect it.

Overload Fault – EPS Mode Overload

Too much power is being drawn in Emergency Power Supply (EPS) mode. Turn off high-power appliances and press ‘ESC’ to reset the inverter. If the SolaX error code doesn’t clear, contact a professional.

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Please reach out to us anytime on the below methods if you are unsure or would like to book an inspection

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EPS OCP Fault – Overcurrent in EPS Mode

This SolaX inverter fault occurs when the power load exceeds EPS capabilities. Remove any non-linear loads and restart the inverter. If the error remains, seek expert support.

DCI Device Fault – DC Injection Device Malfunction

A fault in the DCI system has been detected. Fully shut down your system and restart it. If the issue persists, call a solar technician.

EPS Relay Fault – EPS Relay Malfunction

Similar to other relay issues, this means the EPS relay has failed. Restart the system. If the SolaX inverter error doesn’t clear, contact an installer or service technician.

TZ Protect Fault – Overcurrent Protection Triggered

This SolaX error code shows that an overcurrent protection mechanism has been activated. After a full system shutdown and restart, monitor the inverter. If it doesn’t return to normal, further troubleshooting is required.

Grid Lost Fault – No Grid Connection

Your SolaX inverter has lost its connection to the electricity grid. This will usually resolve itself once the grid supply returns to normal.

Grid Volt Fault – Abnormal Grid Voltage

This error appears when the voltage from the grid is outside acceptable limits. The SolaX inverter fault should clear automatically once the voltage stabilises.

Grid Freq Fault – Grid Frequency Error

The grid’s frequency is outside the normal range. Like voltage errors, your inverter should reconnect automatically when the supply returns to normal.

PLL Lost Fault – Grid Sync Failure

The inverter has failed to sync with the grid. This fault should also resolve itself once stable conditions return.

Bus Volt Fault – Bus Voltage Out of Range

The inverter’s internal bus voltage is too high or too low. Try a full shutdown and restart. If the SolaX inverter error persists, call a technician.

AC5M Volt Fault – Grid Voltage Out of Range for 5 Minutes

Grid voltage has been out of spec for over five minutes. The inverter will attempt to reconnect automatically.

Inv OCP Fault – Overcurrent Protection Triggered

Your SolaX inverter detected an overcurrent situation. Wait to see if the error clears. If not, contact a professional.

PV Volt Fault – PV Voltage Error

This SolaX error code suggests an issue with your solar panel output. Compare actual voltage readings with your system specs. If in doubt, get it inspected.

AC10M Volt Fault – Grid Voltage Out of Range for 10 Minutes

Like the 5-minute version, this fault means the grid has been unstable for too long. The system should reconnect once conditions improve.

Isolation Fault – Insulation Issue Detected

There may be a grounding or insulation problem in your system. This SolaX inverter fault should be assessed by a licensed solar technician.

Temp Over Fault – Inverter Overheating

Check that the inverter’s fan is running and that the unit isn’t in a hot environment. If cooling is not effective, professional servicing is required.

Fan1 Speed Fault / Fan2 Speed Fault – Abnormal Fan Speed

The fan is spinning at an unexpected speed. Shut down your inverter and check for blockages. If the issue continues, contact a technician.

C1 CAN – Battery Communication Error

This fault means the inverter can’t communicate with the battery. Check the charger’s communication cable. If reconnecting doesn’t fix it, get expert help.

C1 TEMP – Battery Charger Over Temperature

Your battery charger is running too hot. Check for blocked ventilation and ensure it’s installed in a cool space.

C1 FAN – Battery Charger Fan Error

Dust or debris may be blocking the fan. DO NOT open the inverter—call a professional if the fan isn’t functioning.

C1 TZ Fault – Battery Charger Protection Triggered

Protection circuits in the charger have activated. Wait to see if the SolaX inverter fault clears. If not, seek help.

C1 EEPROM – Battery Charger Memory Error

The EEPROM memory within the charger has experienced a fault. Try restarting. If the error remains, call a technician.

C1 HCT1 Fault / C1 HCT2 Fault – Current Detection Faults

These SolaX error codes relate to current measurement in the charger. Disconnect and reconnect the charger. If unresolved, contact support.

C1 Bus OVP – Charger Bus Voltage Over Limit

The bus voltage has exceeded its safe range. Monitor the system to see if it self-recovers. If not, get help.

C1 Temp Low – Charger Below Minimum Operating Temperature

This typically occurs in very cold environments. Wait for conditions to warm up and check if the error clears.

C1 Boost OVP – Charger Boost Voltage Too High

An internal boost circuit has exceeded safe limits. Wait and monitor. If the SolaX inverter fault continues, get expert support.

C1 Bat OVP – Battery Over Voltage

Your battery voltage is too high. Wait to see if this SolaX error code clears after load balancing.

C1 Charger OCP – Overcurrent Protection Triggered in Charger

Too much current is flowing through the charger. If restarting doesn’t help, contact a technician.

C1 Boost OCP – Boost Circuit Overcurrent

The boost section of the charger has detected excess current. Wait for the system to stabilise or get it checked.

CT Fault – Current Transformer or Smart Meter Error

Check the smart meter in your switchboard. DO NOT open the panel—restart your inverter and call for help if the fault remains.

RC Fault – DCI Overcurrent Fault

A safety feature in the DCI circuit has tripped due to high current. Wait for auto-recovery or arrange an inspection.

DCI OCP Fault – DCI Overcurrent Protection Triggered

Same as above—monitor the system or call a technician if the fault continues.

DM9000 – Network DSP Fault

Restart the system completely. If your SolaX inverter error doesn’t clear, professional assistance is needed.

RTC Fault – Real Time Clock Fault

The inverter’s internal clock has malfunctioned. Restart the inverter. If the fault persists, seek support.

Need Help With a SolaX Inverter Fault? Call Solair Electrical Today

Many SolaX inverter error codes can be triggered by common issues—like unstable grid voltage, overheating, or faulty fan operation—but some are signs of deeper problems like DC injection, relay failure, or EEPROM faults that need professional attention.

At Solair Electrical, we specialise in fault finding and repairs for the full SolaX range, including smart hybrid inverters with battery storage. If your system has stopped working or is flashing an unfamiliar fault code, don’t risk downtime or loss of feed-in—let us inspect, test, and get your inverter back online quickly and safely.

We’re based in Thornlands and service the entire Greater Brisbane area, including Logan, Redlands, and the Gold Coast.

Call 0405 685 441 now to book your SolaX inverter inspection with Solair Electrical—your trusted local solar specialists.