Need help with plumbing repair

I have a union that has connects plumbing to my pump that has broken in two. I need to know what parts I need to repair this and tips on "How To". I believe it is either 1-1/2" or 2". The union is connected to a short piece of pipe that is glued into a Tee.

Attachment 25

We would need to know what the threads measure on the pump to see what size the union is you need. A 2" union will have 3" threads on its OD of the pump. A 1.5" will have 2-3/8" threads on the OD.