I've been reading on both of them. Both say that the other solution will not last 5 years!! Is there anybody with bad experiences with CSV here? Is there anybody with bad experiences with VSD here? From the beginning we were scared a 3 phase motor drive will be sensible elctronic subject to failures... But does having the pump fight against a closed valve is better? Does it really shuts the consumed current? I will run some test with our water pump while I close the main valve this weekend but if anyone has a comment, they are more than welcome! Cheers! Laurence.