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Generac•PV Link

Analysis by Marcus & Team

Generac PV Link Error 206: String Voltage Mismatch

Troubleshoot Generac PV Link Error 206: String voltage mismatch. Diagnose PV array issues, wiring faults, and inverter problems. Ensure NEC compliance.

Frequently Asked Questions

•What is the typical open-circuit voltage (Voc) for my PV modules?

Refer to the PV module datasheet for the Voc specification. This value will vary depending on the module type and temperature.

•How can I safely test PV modules without touching live wires?

Use a multimeter with insulated probes and follow proper lockout/tagout procedures. If you are not comfortable working with high-voltage DC systems, contact a qualified electrician.

•Where can I find the Generac PV Link service manual?

The service manual can be downloaded from the Generac website or obtained from your installer or a Generac authorized service provider.

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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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Safety Warning:

PV systems operate at high DC voltages (up to 600V or more), posing a significant electrical shock hazard. Arc flash is a serious risk. Always de-energize the system before performing any maintenance or troubleshooting. Follow NEC rapid shutdown procedures and wear appropriate personal protective equipment (PPE), including insulated gloves and safety glasses. Only qualified electricians should work on PV systems.

Step-by-Step Fix:

1

*Safety First**: De-energize the PV system by disconnecting the DC disconnect switch located near the inverter and at the PV array (if present). Verify zero voltage using a calibrated multimeter.
2

*Visual inspection**: Thoroughly inspect all PV modules for physical damage (cracks, delamination, burn marks). Check wiring connections for corrosion, looseness, and proper torque.
3

*String Voltage Measurement**: Using a multimeter, measure the open-circuit voltage (Voc) of each PV string at the inverter's DC input terminals. Compare the readings. A significant difference indicates a fault in the lower-voltage string. Record all measurements.
4

*Module-Level Testing (If Safe and Necessary)**: If string voltage disparities are identified, use a multimeter to measure the voltage of individual PV modules within the suspect string. Identify any modules with significantly lower or zero voltage. *Note: Avoid touching exposed conductors. Use insulated probes.* If safe access is not possible due to height or other hazards, further module-level testing requires a qualified technician with appropriate safety equipment.
5

*Wiring Continuity Test**: With the system de-energized, use a multimeter to perform a continuity test on the wiring of the suspect string. Check for open circuits or short circuits.
6

*Diode Testing**: Use a multimeter with diode test function to check the bypass diodes within each PV module. A failed bypass diode can cause a voltage drop.
7

*Inverter Diagnostics**: If the PV array and wiring appear to be in good condition, the inverter's MPPT circuit may be faulty. Consult the Generac PV Link service manual for troubleshooting procedures. Contact Generac technical support for further assistance. Re-energize the system after all checks are satisfactory and monitor string voltages using the inverter's monitoring app. Observe for Error 206 recurrence.

Technical Overview:

The Generac PV Link is a hybrid inverter that manages power flow between PV arrays, battery storage, and the grid. It utilizes multiple MPPT (Maximum Power Point Tracking) circuits to optimize energy harvest from individual PV strings. Error 206 signifies that the voltage difference between these strings exceeds a predefined threshold. This discrepancy can stem from module failures, wiring issues, or inverter hardware problems. Rapid shutdown (RSD) functionality, as required by NEC 2017/2020, must be considered during troubleshooting.

Common Causes:

Open circuit in one or more PV modules within a string.
Short circuit in one or more PV modules within a string.
Loose or corroded wiring connections in the PV array or combiner box.
Mismatched PV module types or orientations within a string.
Failure of a string diode or bypass diode within a PV module.
Inverter MPPT circuit malfunction.

Observed Symptoms:

Generac PV Link hybrid inverter displays Error 206, indicating a significant voltage difference between PV input strings. Reduced or no power production from the PV array. The inverter may shut down or operate intermittently. Monitoring app may show abnormal string voltages.

Preventative Care:

Regularly inspect PV array wiring and connections for corrosion or damage
Perform periodic string voltage checks using the inverter's monitoring system or a multimeter
Ensure all PV modules are of the same type and orientation within each string
Schedule licensed technician maintenance checks annually