Hi Megafly, I'm very sorry about this problem. This occurs in a small percentage of 140 and 170s before the latest generation of shaft tunnel is implemented. This temporary binding is only during cool down, once in operating temperature it has absolutely no bearing to its operation and should clear up in time with more temperature fluctuation cycles. Just in case if you can not tolerate it, please have it sent back to the factory for an upgrade. Otherwise, you can count on a good discount on your next turbine if you could "deal" with it in case it's going in a boomerang where flicking the rotor isn't too much a problem. Subsequently, a free upgrade will be easily done during a maintenance service.

Barry