3000 watt 6000 watt Surge Power Pure Sine Wave Power Inverter (3000W/24V)

Suspected it was not a pure sine wave. Used a scope and it is a pure sine wave. Then one week in it kept shutting down. It was not hot, under or over volts. Only had 1400 watt resistive load on a 3000 watt inverter. the load was intermittent, maybe 10 minutes at a time, not constant Then the fault light came on. Removed power to drain all caps inside and tried again. I could not get the fault light to clear and there is not output anymore. Only 2 weeks in and had to send it back.