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Generac•PV Link

Analysis by Marcus & Team

Generac PV Link Error 157: SnapRS Overtemperature

Troubleshoot Generac PV Link Error 157 (SnapRS overtemperature). Learn causes, solutions, prevention, and safety for residential solar rapid shutdown systems.

Frequently Asked Questions

•What are the acceptable operating temperature ranges for the SnapRS devices?

Refer to the Generac PV Link installation manual for the specific operating temperature ranges of the SnapRS devices. Ensure the ambient temperature and ventilation meet these requirements.

•How do I verify that the rapid shutdown system is functioning correctly?

After initiating rapid shutdown, use a calibrated multimeter to verify that the voltage at the PV module string is reduced to less than 30V within 30 seconds, as required by NEC 690.12.

•What is the warranty coverage for the SnapRS devices?

Consult the Generac warranty documentation for the PV Link system to determine the warranty coverage period and conditions for the SnapRS devices. Keep records of all maintenance and repairs to support warranty claims.

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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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Observed Symptoms:

PV Link reports Error 157 indicating an overtemperature condition detected in a SnapRS rapid shutdown device. The system may shut down or reduce power output to prevent thermal damage. Monitoring app displays the error, and inverter may display a corresponding warning.

Important Warnings:

High DC voltage is present in PV systems. Always disconnect both AC and DC power before performing any maintenance or troubleshooting. Use appropriate personal protective equipment (PPE), including insulated gloves and eye protection. Do not work on live circuits. Only qualified electricians should perform repairs on PV systems, complying with NEC Article 690.

Technical Background:

Generac PV Link utilizes SnapRS devices for module-level rapid shutdown compliance according to NEC 2017/2020. These devices reduce voltage to <30V within 30 seconds upon initiation of rapid shutdown. Overtemperature protection is built into the SnapRS to prevent thermal runaway. The SnapRS communicates its temperature status to the inverter. Excessive current, poor ventilation, or component failure can trigger the overtemperature fault.

Step-by-Step Fix:

1

Disconnect the AC power to the Generac inverter and engage the DC disconnect switch. Verify voltage is reduced to safe levels (<30V) at the PV module string using a calibrated multimeter.
2

Allow the system to cool down completely. Use an IR thermometer to measure the temperature of each SnapRS device. Compare readings to identify the overheating unit.
3

Inspect the wiring connections to the affected SnapRS for looseness or corrosion. Tighten or replace connections as needed, ensuring proper torque.
4

Measure the current flowing through the affected SnapRS using a clamp meter. Compare to the PV module's rated short-circuit current (Isc) to identify potential overcurrent conditions. Address any shading or panel mismatch issues.
5

If the SnapRS consistently overheats under normal operating conditions, replace it with a new unit from Generac. Ensure the replacement unit is compatible with the PV Link system.
6

After replacing the SnapRS, monitor the system performance using the Generac monitoring app. Verify that Error 157 is cleared and the system operates within normal temperature ranges.
7

Document all findings and actions taken in a service report, including SnapRS serial numbers and temperature readings. Comply with NEC 690.12 for rapid shutdown systems.

Possible Causes:

High ambient temperature exceeding SnapRS operating limits.
Insufficient ventilation around the PV modules or SnapRS devices.
Excessive current flow through the SnapRS due to panel mismatch or shading.
Internal component failure within the SnapRS, such as a MOSFET or diode.
Loose wiring connections causing increased resistance and heat generation.
Degradation of thermal interface material between the SnapRS and the PV module.

Prevention:

Schedule annual system inspections to check for loose wiring connections, adequate ventilation, and proper SnapRS operation
Clean PV modules regularly to prevent shading and maintain optimal current flow
Monitor system performance through the Generac app for any signs of overtemperature or reduced output
Ensure the inverter and SnapRS firmware are up to date