Their website leaves a lot to be desired. All I can suggest is calling or emailing them. Whether or not they'll hook you up with a service manual, I can't say.
While we're on the subject, it's puzzling to me how some manufacturers gladly offer their service manuals while others guard them as if they're top secret. For example, Ice-O-Matic offers owner/instruction manuals, service manuals (along with service bulletins) and training videos! How cool is that?
On the other hand, Hobart/Traulsen, like Rational and many others, offer very little, if any, service help in the way of literature. Some customers have their own in-house service technicians and may have purchased thousands upon thousands of dollars of their equipment, not to mention parts, yet they won't let go of a service manual. I finally was able to pry loose a Hobart dishwasher service manual form Hobart after many emails. I'm still working on Groen. They offered to sell me a $50 service manual on CD for one of their steamers, but I refuse to pay for a manual on a CD or in a PDF file. I might buy a printed version, but that would depend.
Anyway, I wish you good luck in getting your manual. Let us know how it goes.
They are generally only available if you take their training, and on the service portal website which you need a password for. About the only thing you can do is call them and see if they will send you one.