I think you will have to pay for all of them, because 1. after the handover of the house, the burden of proof is on your side and 2. there is absolutely no warranty on rotating/movable parts. If it is something else, you also cannot prove that it was already defective at the time of the house handover (after all, it worked for 3 years). Unfortunately, your maintenance won’t help you either, even if, for example, the lifting system motor fails one day later. You can only hope for goodwill, but I don’t see any warranty claim here.