Before you buy a Nelson Rotor read this!
Run for the hills I have a house that is 11 years old and the rotors are starting to go, I have a variety of brands unfortunately but good for you. I have the Rainbird 5000, Wheathermatic Turbo 3, Toro and Nelson 6000. This year when I opened up the system I had to replace, you guesed it 4 Nelsons what a peice of garbage!!!!!!!!! they stick dont rotate and did not last. Spend your money wisely, I put in new Hunter PGP's and new hunter rain sensor so far so good. O'h by the way two more Nelsons gave out on me again, hence the great publicity.
If Hunter did not have such a great name in the business I would have no problem with installing the Rainbirds they have been flawless in performanace. Regards a plumbers son.