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Unspecified•Microinverter

Analysis by Marcus & Team

Unspecified Microinverter Internal Temperature Error

Diagnosing the Internal Temperature Error in a residential microinverter system. Causes, solutions, and safety advice for homeowners. Call a qualified electrician.

Frequently Asked Questions

•What is the typical lifespan of a microinverter?

Microinverters typically have a lifespan of 15-25 years, but this can vary depending on environmental factors and operating conditions.

•Can I replace a microinverter myself?

Replacing a microinverter should only be done by a qualified electrician due to the high voltage hazards involved and the need to ensure proper grounding and wiring.

•How do I know if my microinverter is overheating?

Signs of an overheating microinverter include reduced power output, error messages in the monitoring system, and a physically hot microinverter. Contact a qualified electrician immediately if you suspect overheating.

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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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Why This Happens:

Insufficient Ventilation: The microinverter is installed in a location with poor airflow, such as under a tight-fitting PV module or near obstructions.
Component Failure: A critical component (e.g., capacitor, MOSFET) inside the microinverter has failed, generating excessive heat.
Overloading: The PV module is producing more power than the microinverter is rated for, leading to overheating.
Ambient Temperature: Excessively high ambient temperature exceeding the microinverter's operational range.
Firmware Bug: A software error is causing the temperature sensor to report incorrect readings or is misinterpreting valid readings.
Damaged Heat Sink: The heat sink designed to dissipate heat from the internal components is damaged or blocked by debris.

Important Warnings:

Microinverters operate at high voltages and can pose a significant electrical shock hazard. Always disconnect the AC and DC power to the microinverter before performing any maintenance or inspection. Adhere to NEC rapid shutdown requirements and consult with a qualified electrician for any repairs or replacements. Working on live circuits is strictly prohibited. Severe arc flash and electrocution hazards are present.

Observed Symptoms:

The microinverter reports an "Internal Temperature Error" via the monitoring system (app or web interface). Power production from the affected PV module is reduced or completely stopped. The microinverter may be physically hot to the touch, but this is not always the case.

Recommended Action:

1

Disconnect the AC power to the PV system at the service panel.
2

Engage rapid shutdown (RSD) by switching the RSD initiator switch to the OFF position per NEC 690.12 requirements. Use a multimeter to verify voltage is below 30V within the RSD boundary.
3

Visually inspect the microinverter for any signs of damage, such as bulging capacitors or burn marks. Document with photos.
4

Check the microinverter's system location for adequate ventilation. Ensure that there are no obstructions blocking airflow around the unit.
5

Use an IR thermometer to measure the surface temperature of the microinverter and compare it to the manufacturer's specifications. Note: this reading may not reflect internal temperature accurately.
6

Check the PV module's output voltage and current using a multimeter and clamp meter, and compare them to the microinverter's input specifications. Exceeding the microinverter's ratings could cause overheating.
7

Contact a qualified electrician or the microinverter manufacturer for further diagnostics and repair. Do not attempt to disassemble the microinverter yourself.

Technical Overview:

Microinverters convert DC power from a single PV module into AC power directly on the roof. They contain power electronic components (MOSFETs, capacitors, inductors, etc.) that generate heat during operation. A temperature sensor inside the microinverter monitors the internal temperature to prevent overheating and damage. The control system manages MPPT, DC/AC conversion, and grid synchronization. High temperatures can indicate component failure, inadequate cooling, or excessive load.

Expert Tip:

Check the microinverter manufacturer's website or documentation for specific diagnostic procedures or error code interpretations. Some manufacturers provide detailed troubleshooting guides or service menus that can help pinpoint the cause of the "Internal Temperature Error."

Prevention:

Ensure adequate ventilation around the microinverters during system.
Periodically inspect the microinverters for signs of damage or overheating.
Monitor the PV system's performance using the monitoring system and address any anomalies promptly.
Keep the microinverters' firmware up to date to address potential software bugs and improve performance.
Clean any dust or debris from the microinverters' heat sinks to maintain optimal cooling.