[rsynnott]

There's a lot of ambiguity at the edges, on that.

B1 visa (the 'business trip' visa): > A B-1 visa may be granted to specialized workers going to the United States to install, service, or repair commercial or industrial equipment or machinery purchased from a company outside of the United States, or to train U.S. workers to perform such services.

So on the face of it you'd think a B1 visa would be sufficient here.