Howdy, we have a 6040 router that we use to engrave aluminum, and the 2.2kw Huanyang VFD will only turn on if the ambient temperature is under 80 F (27 C). If it's hot, the relay will click on and the screen will light up for a second before shutting off. It will repeat this cycle every 4-5 seconds until unplugged. Is there a thermal protection sensor somewhere that is possibly faulting? Has anyone had a similar problem? Thanks.