Conventional doesn't move in only one direction, I always saw that they move in both. And bigger drums have more disadvantage like unbalance control that takes like lots of minutes. If the LG washer doesn't make it, she ends the cycle and shows UE. And the older machines like 5 or 6 kg just doesn't care about the unbalance and spin.
TE error has nothing to do with the thermostat and all they say is just call their support team until then close the water supply and unplug the washer
I see someone mentioned warranty. Well my experience with LG and their warranty lots to be desired. I don't think it is worth the paper it is written on