So that is 1/6th of what Rossi claims.
In context, if the 60C -> 100C claimed temperature difference is real, that corresponds to:
40C * (5/60)kg/s * 4.2 kJ/kgC = 14kW. Leaving 6kW (I'm supposing 20kW input power, is that correct?) for phase change.
At 2260kJ/kg, and this flowrate, 100% phase change would require:
5/60 kg/s * 2260kJ/kg = 190kW. Thus we have phase change of approximately 3% of the total flow. Two electric kettles worth.
Actually, here is what my spreadsheet looks like at the top...
Pretty close to 1500L (report)/300 (5L*60 minutes from Murray tests)