I need to make sure the Broaster 1800E is wired for single phase and not 3 phase by reviewing a wiring diagram.

If you Google the model, you will see that it can be wired single or 3 phase. http://www.broaster.com/pdfs/lit/1800-lr.pdf

Here is User Manual:
http://steersonline.myhost.co.za/downloads/9.3%2014679-0%201600-1800%20Chicken%20Broaster%20Manual.pdf
And this may help:
http://etna-distribution.eu/upload/hds/Broaster%205-15-09%20List%20Only.pdf
In the manual is says the Diagram is/may be shipped with the Unit?