here is what I want to see. A double-blind experiment, where the suppliers provide the E-cat, sealed if need be. The testers will randomly supply the E-cat with either hydrogen gas (H2) or deuterium gas (D2), or deuterium hydride (DH). The magnitude of the measurable difference should suggest the likelihood of the process being nuclear.
This leaves the last two possibilities:
- Rossi was somehow able to hoodwink fairly capable scientists (inject extra power into the E-Cat without them noticing),
- or he's actually built something interesting.