I have put a new bladder tank in my sons house and it does not seem to be filling with water. I took it off line and looked in the inlet for a plug or something that might be blocking it but all I see is what appears to be the bladder which I would guess to be normal.I put it back online and the tank stays empty -feels like no water at in it.Of course the pump cycles on and off like crazy . Do tanks come bad from the factory sometimes or am I missing something? thanks