W16Fault

Felicity inverter error W16

Clock Warn

Fault — the inverter cuts its output and the red LED stays solid until the fault is cleared.

The exact meaning depends on your model:

E-CHO-SI3KS2

InverterFault

Also applies to:E-CHO-SI5KS2E-CHO-SI8KS2

What it means

Clock Warn — Internal clock/RTC warning, button battery low.

Cause: The internal real-time clock is unreliable because its backup button battery is low, so the inverter may lose time-keeping when powered down.

How to fix it

  1. Power down the inverter, wait 5 minutes for capacitors to discharge, then restart.
  2. If the fault recurs immediately or repeatedly, record the exact code and contact your installer or the manufacturer's service line.

Source: E-CHO-SI3KS2-Operation-Manual.pdf, p.17 · E-CHO-SI5KS2-Operation-Manual.pdf · E-CHO-SI8KS2-Operation-Manual.pdf

T-REX-50KHP3G01

InverterFault

What it means

Ambient overtemperature derating alarm — The ambient temperature is too high, and the inverter reduces the power.

Cause: Inverter internal temperature has exceeded the safe operating threshold. Causes include high ambient temperature, blocked cooling vents, failed cooling fan, or installation in direct sunlight.

How to fix it

  1. Power down the inverter and let it cool.
  2. Inspect cooling vents and fan inlets for dust, leaves, or insect nests — clean with compressed air.
  3. Confirm the inverter is installed in a shaded, ventilated location with the manufacturer's required clearances on all sides.
  4. If the fan does not spin on restart, fan replacement is required.

Source: T-REX-50KHP3G01-user-manual-.pdf, p.45

Frequently asked questions

What does error W16 mean on a Felicity inverter?
It depends on the model — 4 devices use code W16. On the E-CHO-SI3KS2 it means: Clock Warn. The card for each model on this page gives its exact meaning and fix.
Is error W16 a fault or a warning?
W16 is a fault code: the inverter cuts its output and the red LED stays solid until it is cleared.
How do I clear or fix error W16?
Power down the inverter, wait 5 minutes for capacitors to discharge, then restart. If the fault recurs immediately or repeatedly, record the exact code and contact your installer or the manufacturer's service line. The exact steps for each affected model are listed on this page.

Related error codes

Other codes on the E-CHO-SI3KS2

All E-CHO-SI3KS2 codes All E-CHO-SI5KS2 codes All E-CHO-SI8KS2 codes

Other codes on the T-REX-50KHP3G01

All T-REX-50KHP3G01 codes

Prefer the full written guide? Read the complete Felicity inverter error-code guide

Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.