Hello Thomas,
Thank you for the 5 Star review! It is our goal to provide quality products and great customer service. Thank you for taking the time to submit a review.
In response to your question, it will be easier if you can lay the pump down in a horizontal position, but it can be done in a vertical position, it will just be more difficult to align all the parts. We hope this helps. You can also always call our Product Support Team for questions. They can be reached at 1-800-835-0113 Mon. - Fri., 8am - 5pm ( CST).
Have a great day!
Great Plains Industries