If one was to use only 20kW I suppose only about 25 - 30kg kg of saturated steam or so would be produced an hour. This would be about About 0.008 kg/s. that's about half a tablespoon a second. is this right?
Probably, no steam was produced. There must have been some back pressure from the heat exchanger. At these temperatures there was no steam; it was all liquid water.