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Generac•SnapRS

Analysis by Marcus & Team

Generac SnapRS Error 0x7318 Serial Number Mismatch

Troubleshoot Generac SnapRS error 0x7318 (Serial Number Mismatch). Learn causes, solutions, prevention, and safety for residential solar systems.

Frequently Asked Questions

•How do I access the inverter configuration menu to check the SnapRS serial numbers?

The procedure varies depending on the Generac inverter model. Consult the Generac installation manual for your specific inverter. Typically, it involves entering a specific access code or using the Generac Powerplay app with installer credentials.

•What is the NEC requirement for rapid shutdown voltage?

NEC 690.12 requires that the voltage outside the array boundary be reduced to 30V or less within 30 seconds of rapid shutdown initiation.

•How can I tell if a SnapRS unit has failed?

Possible indicators include communication errors, inability to initiate rapid shutdown, physical damage to the unit, or voltage readings that deviate significantly from other units in the string. Use a DC clamp meter to confirm current flow through the unit. Check the Generac installer documentation for troubleshooting guidance.

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Marcus leads the technical research department at Storage Faults. Together with a team of systems analysts, he specializes in translating complex solar storage error codes into actionable diagnostic steps for the US market.

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Technical Overview:

The Generac SnapRS system utilizes a proprietary communication protocol to verify the identity and operational status of each RSD unit. This verification is essential for NEC 2017/2020 compliance (690.12) requiring module-level rapid shutdown. The inverter needs to recognize each SnapRS serial number to ensure proper control and monitoring during rapid shutdown initiation. A mismatch disrupts this process, potentially preventing the inverter from correctly disconnecting PV modules from the DC bus.

Symptoms:

SnapRS unit reports error code 0x7318, indicating a serial number mismatch between the SnapRS device and the inverter or monitoring system. The system may not initiate rapid shutdown as intended.

Why This Happens:

Important Warnings:

High DC voltage is present in PV systems. Only qualified electricians should perform diagnostic and repair procedures. Follow proper lockout/tagout procedures before working on any electrical components. Ensure the rapid shutdown system is functioning correctly before energizing the system. Wear appropriate PPE, including insulated gloves and safety glasses.

Recommended Action:

1

Verify the serial number of each SnapRS unit using a barcode scanner or by manually inspecting the label. Record the serial number of each SnapRS unit and its corresponding PV module location.
2

Access the inverter configuration menu (requires qualified electrician). Review the list of registered SnapRS serial numbers and compare it to the recorded serial numbers. Use the Generac installer portal for best practices.
3

Correct any serial number discrepancies in the inverter configuration. Save the changes and allow the system to reboot.
4

Initiate a manual rapid shutdown test via the inverter interface. Use a multimeter to verify that the voltage at each PV module drops below 30V within 30 seconds, as per NEC 690.12 requirements. Check each PV string.
5

If the error persists, use the Generac Powerplay app to check the software version and download the latest firmware updates for the inverter and SnapRS units. Verify firmware compatibility.
6

If updating firmware doesn't resolve the issue, use a DC clamp meter to measure the current through each PV string. This helps identify any faulty SnapRS unit that may be causing a communication error.
7

Replace any faulty SnapRS units. Update the serial number list on the inverter.

Prevention:

Maintain accurate records of all SnapRS serial numbers and their corresponding PV module locations.
Regularly check the inverter monitoring system for any error messages related to SnapRS communication.
Perform routine firmware updates for the inverter and SnapRS units.
During system, double-check serial number entries in the inverter configuration.
Implement a commissioning checklist including the validation of proper serial number configuration.