Well, I’ve tied what Nick has suggested by making sure they are not over tight and then ‘reset’ the actuators and, initially they work ok, however, after a period of time (24 hours) some decide to go back to remaining open despite no call for heat. To be honest I’ve given up and asked Wunda to refund my money unless they can provide a definitive answer on why this continues to happen and revert back to ‘normal actuators. It will be interesting to see what they say!’