The us patent application contains this statement..
[0060]A practical embodiment of the inventive apparatus, installed on Oct. 16, 2007, is at present perfectly operating 24 hours per day, and provides an amount of heat sufficient to heat the factory of the Company EON of via Carlo Ragazzi 18, at Bondeno (Province of Ferrara).
http://www.google.com/patents/about?id=84vwAAAAEBAJ&dq=US20110005506
This fits with the historical tidbits Rossi has mentioned....that he first discovered (or re-discovered) the anomalous excess heat with just hydrogen and nickel.