I have a sanipump that does not stop pumping when it is used?

My sanipump does not cut out when in use. Took it apart, pump runs normally . Connected it back together turned on tap water was pumping out but would not cut out . Water was still in macerator. Discovered water was ruunning out of return valve as I didn't tighten connection properly. Could return valve be the cause of my problem

Mike
September 2010