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3901/3902

Waiting for DC start conditions > Start cond. not met

SMA · Sunny Boy Solar Inverter

What does 3901/3902 mean?

The necessary feed-in conditions for the utility grid have not yet been fulfilled, preventing the inverter from starting operation. This is often related to environmental conditions or initial setup parameters.

Common Causes

  • PV array is covered by snow or otherwise shaded, reducing power output.
  • Insufficient solar irradiation to meet minimum operating thresholds.
  • The voltage limit for starting grid feed-in is set too high (parameter `Critical voltage to start feed-in`).
  • PV array is incorrectly rated for the inverter's start-up requirements.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Ensure that the PV array is not covered by snow or otherwise shaded.

  2. 2

    Wait for higher solar irradiation levels.

  3. 3

    If this message is displayed frequently in the morning, increase the voltage limit for starting grid feed-in by changing the parameter `Critical voltage to start feed-in`.

  4. 4

    If this message is displayed frequently with medium irradiation, ensure that the PV array is correctly rated for the inverter.

Browse all codes in this manual (23)
Verified technical data. Last updated: April 2026

Related Faults

101Grid fault10252[Interface]: communication disrupted10253[Interface]: connection speed goes to [100 Mbit / 10 Mbit]
Source: SMA Sunny Boy Solar Inverter
Open Manual (Page 52)Search more codes in this manual