660 unit immediately shuts off.

Hi,

Just wanted to get some help with my aquarium lighting setup.

My set up is four all new 110 Watt T12 48" VHO bulbs (from UV lighting company model 454), new 660 ballast, wiring checks out OK, have tried reseating one bulb so far, but I have noticed that in the fraction of a second after you turn the unit on, all bulbs light up and look normal, but only for that fraction of a second before the unit immediately shuts off. It happens as fast as you can get the word "Bob" out of saying "Bob's your Uncle."

I used butt joint connectors (same as in the unit I am replacing that ran for over 10 years.) I used the new wiring harness and the four fluorescent tube diagram for the wiring. I retightened all the connections.

What can you suggest to try and get this to work. What makes the unit shut down?

David.