Hoymiles Error Code 121 – Meaning, Causes & Solution -... | solardiagnostics.org

Technical Background:

Error 121 is an overtemperature fault, indicating that the inverter has detected a temperature exceeding its safe operational threshold. Inverters are equipped with internal temperature sensors that monitor the heat generated during operation. If the internal temperature surpasses the specified limit due to insufficient cooling or external environmental factors, the inverter will trigger this fault to prevent damage. The inverter's safety protocols are designed to protect both the device and the solar array from potential overheating, which can lead to electrical failures or fire hazards.

Symptoms:

When the Hoymiles inverter triggers Error 121, users may observe a red LED indicator flashing, indicating a fault condition. Additionally, the monitoring app may display alerts about reduced energy production or operational status, often showing a significant drop in output power compared to normal performance. Users may also notice the inverter ceasing operation entirely during peak sunlight hours.

Possible Causes:

Insufficient ventilation around the inverter leading to overheating.
High ambient temperatures exceeding the inverter's operational limits.
Faulty temperature sensors within the inverter.
Accumulation of dust or debris obstructing cooling vents.
Overcurrent conditions due to mismatched array configurations or shading issues.

Solution:

1

Inspect the inverter’s system location for adequate airflow; ensure there are no obstructions.
2

Measure the ambient temperature using a digital thermometer to confirm it is within the inverter’s specified limits (typically 32°F to 140°F).
3

Check for any visible dust or debris on the inverter and clean the cooling vents with a soft brush or compressed air.
4

Use a multimeter to verify the output voltage and current from the solar array; ensure it matches the inverter's specifications.
5

Inspect the string configuration for any shading or mismatch that could lead to excessive current draw, and correct as necessary.
6

If the fault persists, consult the inverter's manual to perform a factory reset or contact Hoymiles support for further diagnostics.
7

Document all findings and steps taken for future reference.

Safety Warning:

Always consult a licensed electrician or certified solar installer for troubleshooting and repairs to ensure safety and compliance with electrical codes.

Prevention:

To avoid encountering Error 121 in the future, ensure that the inverter is installed in a well-ventilated area away from direct sunlight and heat sources. Regularly clean the inverter's exterior and cooling vents to prevent dust accumulation. Monitor the system's performance through the app and address any shading or configuration issues promptly. Schedule routine maintenance checks with a certified solar installer to ensure optimal system performance.

Frequently Asked Questions

•What causes the Hoymiles Overtemperature error?

The Overtemperature error can be caused by excessive heat due to poor ventilation or high ambient temperatures. It's essential to ensure proper airflow around the inverter.

•How can I prevent future Overtemperature errors?

To prevent future errors, regularly check the installation site for adequate cooling and avoid placing the inverter in direct sunlight. Consider installing additional ventilation if necessary.

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Frequently Asked Questions

•What causes the Hoymiles Overtemperature error?

•How can I prevent future Overtemperature errors?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention: